,picture3 ,book cover ,,the ,,formation ,,of ,,vegetable ,,mould ,,through ,,the ,,action ,,of ,,worms ,,with ,,observations ,,on ,,their ,,habits4 ,,by ,,charles ,,darwin1 ,,ll4,d41 ,f4,r4,s4 ,,thirteenth ,,thousand ,,with ,,illustrations 99 99 99 99 99 ,,london ,,john ,,murray1 ,,albemarle ,,street #aijd 99 99 99 99 99 ,,printed ,,by ,,william ,,clowes ,,and ,,sons1 ,,limited1 ,,london ,,and ,,beccles4 99 99 99 99 99 ,,contents4 ,,introduction ,page #a-f ,,chapter ,i4 ,,habits ,,of ,,worms4 ,nature of the sites inhabited--,can live long under #g-ae water--,nocturnal--,wander about at night--,often lie close to the mouths of their burrows1 and are thus destroyed in large numbers by birds--,structure--,do not possess eyes1 but can distinguish between light and darkness--,retreat rapidly when brightly illuminated1 not by a reflex action--,power of attention--,sensitive to heat and cold--,completely deaf--,sensitive to vibrations and to touch--,feeble power of smell--,taste--,mental qualities--,nature of food--,omnivorous--,digestion--,leaves before being swallowed1 moistened with a fluid of the nature of the pancreatic secretion--,extra-stomachal digestion--,calciferous glands1 structure of--,calcareous concretions formed in the anterior pair of glands--,the calcareous matter primarily an excretion1 but secondarily serves to neutralise the acids generated during the digestive process4 ,,chapter ,,ii4 ,,habits ,,of ,,worms--continued4 ,manner in which worms seize objects--,their power of #eb-abj suction--,the instinct of plugging up the mouths of their burrows--,stones piled over the burrows--,the advantages thus gained--,intelligence shown by worms in their manner of plugging up their burrows--,various kinds of leaves and other objects thus used--,triangles of paper--,summary of reasons for believing that worms exhibit some intelligence--,means by which they excavate their burrows1 by pushing away the earth and swallowing it--,earth also swallowed for the nutritious matter which it contains--,depth to which worms burrow1 and the construction of their burrows--,burrows lined with castings1 and in the upper part with leaves--,the lowest part paved with little stones or seeds--,manner in which the castings are ejected--,the collapse of old burrows--,distribution of worms--,tower-like castings in ,bengal--,gigantic castings on the ,nilgiri ,mountains--,castings ejected in all countries4 ,,chapter ,,iii4 ,,the ,,amount ,,of ,,fine ,,earth ,,brought ,,up ,,by ,,worms ,,to ,,the ,,surface4 ,rate at which various objects strewed on the surface of #aba-afc grass-fields are covered up by the castings of worms--,the burial of a paved path--,the slow subsidence of great stones left on the surface--,the number of worms which live within a given space--,the weight of earth ejected from a burrow1 and from all the burrows within a given space--,the thickness of the layer of mould which the castings on a given space would form within a given time if uniformly spread out--,the slow rate at which mould can increase to a great thickness--,conclusion4 ,,chapter ,,iv4 ,,the ,,part ,,which ,,worms ,,have ,,played ,,in ,,the ,,burial ,,of ,,ancient ,,buildings4 ,the accumulation of rubbish on the sites of great #afd-bjh cities independent of the action of worms--,the burial of a ,roman villa at ,abinger--,the floors and walls penetrated by worms--,subsidence of a modern pavement--,the buried pavement at ,beaulieu ,abbey--,roman villas at ,chedworth and ,brading--,the remains of the ,roman town at ,silchester--,the nature of the dbris by which the remains are covered--,the penetration of the tesselated floors and walls by worms--,subsidence of the floors--,thickness of the mould--,the old ,roman city of ,wroxeter--,thickness of the mould--,depth of the foundations of some of the ,buildings--,conclusion4 ,,chapter ,v4 ,,the ,,action ,,of ,,worms ,,in ,,the ,,denudation ,,of ,,the ,,land4 ,evidence of the amount of denudation which the land has #bji-bcf undergone--,sub-aerial denudation--,the deposition of dust--,vegetable mould1 its dark colour and fine texture largely due to the action of worms--,the disintegration of rocks by the humus-acids--,similar acids apparently generated within the bodies of worms--,the action of these acids facilitated by the continued movement of the particles of earth--,a thick bed of mould checks the disintegration of the underlying soil and rocks4 ,particles of stone worn or triturated in the gizzards of worms--,swallowed stones serve as mill-stones--,the levigated state of the castings--,fragments of brick in the castings over ancient buildings well rounded4 ,the triturating power of worms not quite insignificant under a geological point of view4 ,,chapter ,,vi4 ,,the ,,denudation ,,of ,,the ,,land--continued4 ,denudation aided by recently ejected castings flowing #bcg-bgi down inclined grass-covered surfaces--,the amount of earth which annually flows downwards--,the effect of tropical rain on worm castings--,the finest particles of earth washed completely away from castings--,the disintegration of dried castings into pellets1 and their rolling down inclined surfaces--,the formation of little ledges on hill-sides1 in part due to the accumulation of disintegrated castings--,castings blown to leeward over level land--,an attempt to estimate the amount thus blown--,the degradation of ancient encampments and tumuli--,the preservation of the crowns and furrows on land anciently ploughed--,the formation and amount of mould over the ,chalk formation4 ,,chapter ,,vii4 ,,conclusion4 ,summary of the part which worms have played in the #bhj-bhh history of the world--,their aid in the disintegration of rocks--,in the denudation of the land--,in the preservation of ancient remains--,in the preparation of the soil for the growth of plants--,mental powers of worms--,conclusion4 ,,introduction4 ,,the share which worms have taken in the formation of the layer of vegetable mould1 which covers the whole surface of the land in every moderately humid country1 is the subject of the present volume4 ,this mould is generally of a blackish colour and a few inches in thickness4 ,in different districts it differs but little in appearance1 although it may rest on various subsoils4 ,the uniform fineness of the particles of which it is composed is one of its chief characteristic features2 and this may be well observed in any gravelly country1 where a recently-ploughed field immediately adjoins one which has long remained undisturbed for pasture1 and where the vegetable mould is exposed on the sides of a ditch or hole4 ,the subject may appear an insignificant one1 but we shall see that it possesses some interest2 and the maxim 8de minimis non curat lex10 does not apply to science4 ,even lie de ,beaumont1 who generally undervalues small agencies and their accumulated effects1 remarks3 #b 8,la couche trs-mince de la terre vgtale est un monument d'une haute antiquit1 et1 par le fait de sa permanence1 un objet digne d'occuper le gologue1 et capable de lui fournir des remarques intressantes40 ,although the superficial layer of vegetable mould as a whole no doubt is of the highest antiquity1 yet in regard to its permanence1 we shall hereafter see reason to believe that its component particles are in most cases removed at not a very slow rate1 and are replaced by others due to the disintegration of the underlying materials4 ,as ,i was led to keep in my study during many months worms in pots filled with earth1 ,i became interested in them1 and wished to learn how far they acted consciously1 and how much mental power they displayed4 ,i was the more desirous to learn something on this head1 as few observations of this kind have been made1 as far as ,i know1 on animals so low in the scale of organization and so poorly provided with sense-organs1 as are earth-worms4 ,in the year #ahcg1 a short paper was read by me before the ,geological ,society of ,london1 #c 8,on the ,formation of ,mould10 in which it was shown that small fragments of burnt marl1 cinders1 c41 which had been thickly strewed over the surface of several meadows1 were found after a few years lying at the depth of some inches beneath the turf1 but still forming a layer4 ,this apparent sinking of superficial bodies is due1 as was first suggested to me by ,mr4 ,wedgwood of ,maer ,hall in ,staffordshire1 to the large quantity of fine earth continually brought up to the surface by worms in the form of castings4 ,these castings are sooner or later spread out and cover up any object left on the surface4 ,i was thus led to conclude that all the vegetable mould over the whole country has passed many times through1 and will again pass many times through1 the intestinal canals of worms4 ,hence the term 8animal mould0 would be in some respects more appropriate than that commonly used of 8vegetable mould40 ,ten years after the publication of my paper1 ,m4 ,d',archiac1 evidently influenced by the doctrines of lie de ,beaumont1 wrote about my 8singulire thorie10 and objected that it could apply only to 8les prairies basses et humides20 and that 8les terres laboures1 les bois1 les prairies leves1 n'apportent aucune preuve l'appui de cette manire de voir40 #d;a ,but ,m4 ,d',archiac must have thus argued from inner consciousness and not from observation1 for worms abound to an extraordinary degree in kitchen gardens where the soil is continually worked1 though in such loose soil they generally deposit their castings in any open cavities or within their old burrows instead of on the surface4 ,hensen estimates that there are about twice as many worms in gardens as in corn-fields4 #d;b ,with respect to 8prairies leves10 ,i do not know how it may be in ,france1 but nowhere in ,england have ,i seen the ground so thickly covered with castings as on commons1 at a height of several hundred feet above the sea4 ,in woods again1 if the loose leaves in autumn are removed1 the whole surface will be found strewed with castings4 ,dr4 ,king1 the superintendent of the ,botanic ,garden in ,calcutta1 to whose kindness ,i am indebted for many observations on earth-worms1 informs me that he found1 near ,nancy in ,france1 the bottom of the ,state forests covered over many acres with a spongy layer1 composed of dead leaves and innumerable worm-castings4 ,he there heard the ,professor of 8,amnagement des ,forts0 lecturing to his pupils1 and pointing out this case as a 8beautiful example of the natural cultivation of the soil2 for year after year the thrown-up castings cover the dead leaves2 the result being a rich humus of great thickness40 ,in the year #ahfi1 ,mr4 ,fish #e rejected my conclusions with respect to the part which worms have played in the formation of vegetable mould1 merely on account of their assumed incapacity to do so much work4 ,he remarks that 8considering their weakness and their size1 the work they are represented to have accomplished is stupendous40 ,here we have an instance of that inability to sum up the effects of a continually recurrent cause1 which has often retarded the progress of science1 as formerly in the case of geology1 and more recently in that of the principle of evolution4 ,although these several objections seemed to me to have no weight1 yet ,i resolved to make more observations of the same kind as those published1 and to attack the problem on another side2 namely1 to weigh all the castings thrown up within a given time in a measured space1 instead of ascertaining the rate at which objects left on the surface were buried by worms4 ,but some of my observations have been rendered almost superfluous by an admirable paper by ,hensen1 already alluded to1 which appeared in #ahgg4 #f ,before entering on details with respect to the castings1 it will be advisable to give some account of the habits of worms from my own observations and from those of other naturalists4 ,,first ,,edition1 ,october #ajth1 #ahha4 ,,chapter ,i4 ,,habits ,,of ,,worms4 ,nature of the sites inhabited--,can live long under water--,nocturnal--,wander about at night--,often lie close to the mouths of their burrows1 and are thus destroyed in large numbers by birds--,structure--,do not possess eyes1 but can distinguish between light and darkness--,retreat rapidly when brightly illuminated1 not by a reflex action--,power of attention--,sensitive to heat and cold--,completely deaf--,sensitive to vibrations and to touch--,feeble power of smell--,taste--,mental qualities--,nature of food--,omnivorous--,digestion--,leaves before being swallowed1 moistened with a fluid of the nature of the pancreatic secretion--,extra-stomachal digestion--,calciferous glands1 structure of--,calcareous concretions formed in the anterior pair of glands--,the calcareous matter primarily an excretion1 but secondarily serves to neutralise the acids generated during the digestive process4 ,,earth-,,worms are distributed throughout the world under the form of a few genera1 which externally are closely similar to one another4 ,the ,british species of ,lumbricus have never been carefully monographed2 but we may judge of their probable number from those inhabiting neighbouring countries4 ,in ,scandinavia there are eight species1 according to ,eisen2 #h;a but two of these rarely burrow in the ground1 and one inhabits very wet places or even lives under the water4 ,we are here concerned only with the kinds which bring up earth to the surface in the form of castings4 ,hoffmeister says that the species in ,germany are not well known1 but gives the same number as ,eisen1 together with some strongly marked varieties4 #h;b ,earth-worms abound in ,england in many different stations4 ,their castings may be seen in extraordinary numbers on commons and chalk-downs1 so as almost to cover the whole surface1 where the soil is poor and the grass short and thin4 ,but they are almost or quite as numerous in some of the ,london parks1 where the grass grows well and the soil appears rich4 ,even on the same field worms are much more frequent in some places than in others1 without any visible difference in the nature of the soil4 ,they abound in paved court-yards close to houses2 and an instance will be given in which they had burrowed through the floor of a very damp cellar4 ,i have seen worms in black peat in a boggy field2 but they are extremely rare1 or quite absent in the drier1 brown1 fibrous peat1 which is so much valued by gardeners4 ,on dry1 sandy or gravelly tracks1 where heath with some gorse1 ferns1 coarse grass1 moss and lichens alone grow1 hardly any worms can be found4 ,but in many parts of ,england1 wherever a path crosses a heath1 its surface becomes covered with a fine short sward4 ,whether this change of vegetation is due to the taller plants being killed by the occasional trampling of man and animals1 or to the soil being occasionally manured by the droppings from animals1 ,i do not know4 #i;b ,on such grassy paths worm-castings may often be seen4 ,on a heath in ,surrey1 which was carefully examined1 there were only a few castings on these paths1 where they were much inclined2 but on the more level parts1 where a bed of fine earth had been washed down from the steeper parts and had accumulated to a thickness of a few inches1 worm-castings abounded4 ,these spots seemed to be overstocked with worms1 so that they had been compelled to spread to a distance of a few feet from the grassy paths1 and here their castings had been thrown up among the heath2 but beyond this limit1 not a single casting could be found4 ,a layer1 though a thin one1 of fine earth1 which probably long retains some moisture1 is in all cases1 as ,i believe1 necessary for their existence2 and the mere compression of the soil appears to be in some degree favourable to them1 for they often abound in old gravel walks1 and in foot-paths across fields4 ,beneath large trees few castings can be found during certain seasons of the year1 and this is apparently due to the moisture having been sucked out of the ground by the innumerable roots of the trees2 for such places may be seen covered with castings after the heavy autumnal rains4 ,although most coppices and woods support many worms1 yet in a forest of tall and ancient beech-trees in ,knole ,park1 where the ground beneath was bare of all vegetation1 not a single casting could be found over wide spaces1 even during the autumn4 ,nevertheless1 castings were abundant on some grass-covered glades and indentations which penetrated this forest4 ,on the mountains of ,north ,wales and on the ,alps1 worms1 as ,i have been informed1 are in most places rare2 and this may perhaps be due to the close proximity of the subjacent rocks1 into which worms cannot burrow during the winter so as to escape being frozen4 ,dr4 ,mc,intosh1 however1 found worm-castings at a height of #aejj feet on ,schiehallion in ,scotland4 ,they are numerous on some hills near ,turin at from #bjjj to #cjjj feet above the sea1 and at a great altitude on the ,nilgiri ,mountains in ,south ,india and on the ,himalaya4 ,earth-worms must be considered as terrestrial animals1 though they are still in one sense semi-aquatic1 like the other members of the great class of annelids to which they belong4 ,m4 ,perrier found that their exposure to the dry air of a room for only a single night was fatal to them4 ,on the other hand he kept several large worms alive for nearly four months1 completely submerged in water4 #aa ,during the summer when the ground is dry1 they penetrate to a considerable depth and cease to work1 as they do during the winter when the ground is frozen4 ,worms are nocturnal in their habits1 and at night may be seen crawling about in large numbers1 but usually with their tails still inserted in their burrows4 ,by the expansion of this part of their bodies1 and with the help of the short1 slightly reflexed bristles1 with which their bodies are armed1 they hold so fast that they can seldom be dragged out of the ground without being torn into pieces4 #ab ,during the day they remain in their burrows1 except at the pairing season1 when those which inhabit adjoining burrows expose the greater part of their bodies for an hour or two in the early morning4 ,sick individuals1 which are generally affected by the parasitic larv of a fly1 must also be excepted1 as they wander about during the day and die on the surface4 ,after heavy rain succeeding dry weather1 an astonishing number of dead worms may sometimes be seen lying on the ground4 ,mr4 ,galton informs me that on one such occasion 7,march1 #ahha71 the dead worms averaged one for every two and a half paces in length on a walk in ,hyde ,park1 four paces in width4 ,he counted no less than #de dead worms in one place in a length of sixteen paces4 ,from the facts above given1 it is not probable that these worms could have been drowned1 and if they had been drowned they would have perished in their burrows4 ,i believe that they were already sick1 and that their deaths were merely hastened by the ground being flooded4 ,it has often been said that under ordinary circumstances healthy worms never1 or very rarely1 completely leave their burrows at night2 but this is an error1 as ,white of ,selborne long ago knew4 ,in the morning1 after there has been heavy rain1 the film of mud or of very fine sand over gravel-walks is often plainly marked with their tracks4 ,i have noticed this from ,august to ,may1 both months included1 and it probably occurs during the two remaining months of the year when they are wet4 ,on these occasions1 very few dead worms could anywhere be seen4 ,on ,january #ca1 #ahha1 after a long-continued and unusually severe frost with much snow1 as soon as a thaw set in1 the walks were marked with innumerable tracks4 ,on one occasion1 five tracks were counted crossing a space of only an inch square4 ,they could sometimes be traced either to or from the mouths of the burrows in the gravel-walks1 for distances between #b or #c up to #ae yards4 ,i have never seen two tracks leading to the same burrow2 nor is it likely1 from what we shall presently see of their sense-organs1 that a worm could find its way back to its burrow after having once left it4 ,they apparently leave their burrows on a voyage of discovery1 and thus they find new sites to inhabit4 ,morren states #ad that worms often lie for hours almost motionless close beneath the mouths of their burrows4 ,i have occasionally noticed the same fact with worms kept in pots in the house2 so that by looking down into their burrows1 their heads could just be seen4 ,if the ejected earth or rubbish over the burrows be suddenly removed1 the end of the worm's body may very often be seen rapidly retreating4 ,this habit of lying near the surface leads to their destruction to an immense extent4 ,every morning during certain seasons of the year1 the thrushes and blackbirds on all the lawns throughout the country draw out of their holes an astonishing number of worms1 and this they could not do1 unless they lay close to the surface4 ,it is not probable that worms behave in this manner for the sake of breathing fresh air1 for we have seen that they can live for a long time under water4 ,i believe that they lie near the surface for the sake of warmth1 especially in the morning2 and we shall hereafter find that they often coat the mouths of their burrows with leaves1 apparently to prevent their bodies from coming into close contact with the cold damp earth4 ,it is said that they completely close their burrows during the winter4 ,structure4--,a few remarks must be made on this subject4 ,the body of a large worm consists of from #ajj to #bjj almost cylindrical rings or segments1 each furnished with minute bristles4 ,the muscular system is well developed4 ,worms can crawl backwards as well as forwards1 and by the aid of their affixed tails can retreat with extraordinary rapidity into their burrows4 ,the mouth is situated at the anterior end of the body1 and is provided with a little projection 7lobe or lip1 as it has been variously called7 which is used for prehension4 ,internally1 behind the mouth1 there is a strong pharynx1 shown in the accompanying diagram 7,fig4 #a7 which is pushed forwards when the animal eats1 and this part corresponds1 according to ,perrier1 with the protrudable trunk or proboscis of other annelids4 ,the pharynx leads into the sophagus1 on each side of which in the lower part there are three pairs of large glands1 which secrete a surprising amount of carbonate of lime4 ,these calciferous glands are highly remarkable1 for nothing like them is known in any other animal4 ,their use will be discussed when we treat of the digestive process4 ,in most of the species1 the sophagus is enlarged into a crop in front of the gizzard4 ,this latter organ is lined with a smooth thick chitinous membrane1 and is surrounded by weak longitudinal1 but powerful transverse muscles4 ,perrier saw these muscles in energetic action2 and1 as he remarks1 the trituration of the food must be chiefly effected by this organ1 for worms possess no jaws or teeth of any kind4 ,grains of sand and small stones1 from the #a_/bj to a little more than the #a_/aj inch in diameter1 may generally be found in their gizzards and intestines4 ,as it is certain that worms swallow many little stones1 independently of those swallowed while excavating their burrows1 it is probable that they serve1 like mill-stones1 to triturate their food4 ,the gizzard opens into the intestine1 which runs in a straight course to the vent at the posterior end of the body4 ,the intestine presents a remarkable structure1 the typhlosolis1 or1 as the old anatomists called it1 an intestine within an intestine2 and ,claparde #ag has shown that this consists of a deep longitudinal involution of the walls of the intestine1 by which means an extensive absorbent surface is gained4 ,picture3 ,fig4 #a3 ,diagram of the alimentary canal of an earth-worm4 ,fig4 #b3 ,tower-like casting from near ,nice ,the circulatory system is well developed4 ,worms breathe by their skin1 as they do not possess any special respiratory organs4 ,the two sexes are united in the same individual1 but two individuals pair together4 ,the nervous system is fairly well developed2 and the two almost confluent cerebral ganglia are situated very near to the anterior end of the body4 ,senses4--,worms are destitute of eyes1 and at first ,i thought that they were quite insensible to light2 for those kept in confinement were repeatedly observed by the aid of a candle1 and others out of doors by the aid of a lantern1 yet they were rarely alarmed1 although extremely timid animals4 ,other persons have found no difficulty in observing worms at night by the same means4 #ah;a ,hoffmeister1 however1 states #ah;b that worms1 with the exception of a few individuals1 are extremely sensitive to light2 but he admits that in most cases a certain time is requisite for its action4 ,these statements led me to watch on many successive nights worms kept in pots1 which were protected from currents of air by means of glass plates4 ,the pots were approached very gently1 in order that no vibration of the floor should be caused4 ,when under these circumstances worms were illuminated by a bull's-eye lantern having slides of dark red and blue glass1 which intercepted so much light that they could be seen only with some difficulty1 they were not at all affected by this amount of light1 however long they were exposed to it4 ,the light1 as far as ,i could judge1 was brighter than that from the full moon4 ,its colour apparently made no difference in the result4 ,when they were illuminated by a candle1 or even by a bright paraffin lamp1 they were not usually affected at first4 ,nor were they when the light was alternately admitted and shut off4 ,sometimes1 however1 they behaved very differently1 for as soon as the light fell on them1 they withdrew into their burrows with almost instantaneous rapidity4 ,this occurred perhaps once out of a dozen times4 ,when they did not withdraw instantly1 they often raised the anterior tapering ends of their bodies from the ground1 as if their attention was aroused or as if surprise was felt2 or they moved their bodies from side to side as if feeling for some object4 ,they appeared distressed by the light2 but ,i doubt whether this was really the case1 for on two occasions after withdrawing slowly1 they remained for a long time with their anterior extremities protruding a little from the mouths of their burrows1 in which position they were ready for instant and complete withdrawal4 ,when the light from a candle was concentrated by means of a large lens on the anterior extremity1 they generally withdrew instantly2 but this concentrated light failed to act perhaps once out of half a dozen trials4 ,the light was on one occasion concentrated on a worm lying beneath water in a saucer1 and it instantly withdrew into its burrow4 ,in all cases the duration of the light1 unless extremely feeble1 made a great difference in the result2 for worms left exposed before a paraffin lamp or a candle invariably retreated into their burrows within from five to fifteen minutes2 and if in the evening the pots were illuminated before the worms had come out of their burrows1 they failed to appear4 ,from the foregoing facts it is evident that light affects worms by its intensity and by its duration4 ,it is only the anterior extremity of the body1 where the cerebral ganglia lie1 which is affected by light1 as ,hoffmeister asserts1 and as ,i observed on many occasions4 ,if this part is shaded1 other parts of the body may be fully illuminated1 and no effect will be produced4 ,as these animals have no eyes1 we must suppose that the light passes through their skins1 and in some manner excites their cerebral ganglia4 ,it appeared at first probable that the different manner in which they were affected on different occasions might be explained1 either by the degree of extension of their skin and its consequent transparency1 or by some particular incident of the light2 but ,i could discover no such relation4 ,one thing was manifest1 namely1 that when worms were employed in dragging leaves into their burrows or in eating them1 and even during the short intervals whilst they rested from their work1 they either did not perceive the light or were regardless of it2 and this occurred even when the light was concentrated on them through a large lens4 ,so1 again1 whilst they are paired1 they will remain for an hour or two out of their burrows1 fully exposed to the morning light2 but it appears from what ,hoffmeister says that a light will occasionally cause paired individuals to separate4 ,when a worm is suddenly illuminated and dashes like a rabbit into its burrow--to use the expression employed by a friend--we are at first led to look at the action as a reflex one4 ,the irritation of the cerebral ganglia appears to cause certain muscles to contract in an inevitable manner1 independently of the will or consciousness of the animal1 as if it were an automaton4 ,but the different effect which a light produced on different occasions1 and especially the fact that a worm when in any way employed and in the intervals of such employment1 whatever set of muscles and ganglia may then have been brought into play1 is often regardless of light1 are opposed to the view of the sudden withdrawal being a simple reflex action4 ,with the higher animals1 when close attention to some object leads to the disregard of the impressions which other objects must be producing on them1 we attribute this to their attention being then absorbed2 and attention implies the presence of a mind4 ,every sportsman knows that he can approach animals whilst they are grazing1 fighting or courting1 much more easily than at other times4 ,the state1 also1 of the nervous system of the higher animals differs much at different times1 for instance1 a horse is much more readily startled at one time than at another4 ,the comparison here implied between the actions of one of the higher animals and of one so low in the scale as an earth-worm1 may appear far-fetched2 for we thus attribute to the worm attention and some mental power1 nevertheless ,i can see no reason to doubt the justice of the comparison4 ,although worms cannot be said to possess the power of vision1 their sensitiveness to light enables them to distinguish between day and night2 and they thus escape extreme danger from the many diurnal animals which prey on them4 ,their withdrawal into their burrows during the day appears1 however1 to have become an habitual action2 for worms kept in pots covered by glass plates1 over which sheets of black paper were spread1 and placed before a north-east window1 remained during the day-time in their burrows and came out every night2 and they continued thus to act for a week4 ,no doubt a little light may have entered between the sheets of glass and the blackened paper2 but we know from the trials with coloured glass1 that worms are indifferent to a small amount of light4 ,worms appear to be less sensitive to moderate radiant heat than to a bright light4 ,i judge of this from having held at different times a poker heated to dull redness near some worms1 at a distance which caused a very sensible degree of warmth in my hand4 ,one of them took no notice2 a second withdrew into its burrow1 but not quickly2 the third and fourth much more quickly1 and the fifth as quickly as possible4 ,the light from a candle1 concentrated by a lens and passing through a sheet of glass which would intercept most of the heat-rays1 generally caused a much more rapid retreat than did the heated poker4 ,worms are sensitive to a low temperature1 as may be inferred from their not coming out of their burrows during a frost4 ,worms do not possess any sense of hearing4 ,they took not the least notice of the shrill notes from a metal whistle1 which was repeatedly sounded near them2 nor did they of the deepest and loudest tones of a bassoon4 ,they were indifferent to shouts1 if care was taken that the breath did not strike them4 ,when placed on a table close to the keys of a piano1 which was played as loudly as possible1 they remained perfectly quiet4 ,although they are indifferent to undulations in the air audible by us1 they are extremely sensitive to vibrations in any solid object4 ,when the pots containing two worms which had remained quite indifferent to the sound of the piano1 were placed on this instrument1 and the note ,c in the bass clef was struck1 both instantly retreated into their burrows4 ,after a time they emerged1 and when ,g above the line in the treble clef was struck they again retreated4 ,under similar circumstances on another night one worm dashed into its burrow on a very high note being struck only once1 and the other worm when ,c in the treble clef was struck4 ,on these occasions the worms were not touching the sides of the pots1 which stood in saucers2 so that the vibrations1 before reaching their bodies1 had to pass from the sounding board of the piano1 through the saucer1 the bottom of the pot and the damp1 not very compact earth on which they lay with their tails in their burrows4 ,they often showed their sensitiveness when the pot in which they lived1 or the table on which the pot stood1 was accidentally and lightly struck2 but they appeared less sensitive to such jars than to the vibrations of the piano2 and their sensitiveness to jars varied much at different times4 ,it has often been said that if the ground is beaten or otherwise made to tremble1 worms believe that they are pursued by a mole and leave their burrows4 ,from one account that ,i have received1 ,i have no doubt that this is often the case2 but a gentleman informs me that he lately saw eight or ten worms leave their burrows and crawl about the grass on some boggy land on which two men had just trampled while setting a trap2 and this occurred in a part of ,ireland where there were no moles4 ,i have been assured by a ,volunteer that he has often seen many large earth-worms crawling quickly about the grass1 a few minutes after his company had fired a volley with blank cartridges4 ,the ,peewit 7,tringa vanellus1 ,linn47 seems to know instinctively that worms will emerge if the ground is made to tremble2 for ,bishop ,stanley states 7as ,i hear from ,mr4 ,moorhouse7 that a young peewit kept in confinement used to stand on one leg and beat the turf with the other leg until the worms crawled out of their burrows1 when they were instantly devoured4 ,nevertheless1 worms do not invariably leave their burrows when the ground is made to tremble1 as ,i know by having beaten it with a spade1 but perhaps it was beaten too violently4 ,the whole body of a worm is sensitive to contact4 ,a slight puff of air from the mouth causes an instant retreat4 ,the glass plates placed over the pots did not fit closely1 and blowing through the very narrow chinks thus left1 often sufficed to cause a rapid retreat4 ,they sometimes perceived the eddies in the air caused by quickly removing the glass plates4 ,when a worm first comes out of its burrow1 it generally moves the much extended anterior extremity of its body from side to side in all directions1 apparently as an organ of touch2 and there is some reason to believe1 as we shall see in the next chapter1 that they are thus enabled to gain a general notion of the form of an object4 ,of all their senses that of touch1 including in this term the perception of a vibration1 seems much the most highly developed4 ,in worms the sense of smell apparently is confined to the perception of certain odours1 and is feeble4 ,they were quite indifferent to my breath1 as long as ,i breathed on them very gently4 ,this was tried1 because it appeared possible that they might thus be warned of the approach of an enemy4 ,they exhibited the same indifference to my breath whilst ,i chewed some tobacco1 and while a pellet of cotton-wool with a few drops of millefleurs perfume or of acetic acid was kept in my mouth4 ,pellets of cotton-wool soaked in tobacco juice1 in millefleurs perfume1 and in paraffin1 were held with pincers and were waved about within two or three inches of several worms1 but they took no notice4 ,on one or two occasions1 however1 when acetic acid had been placed on the pellets1 the worms appeared a little uneasy1 and this was probably due to the irritation of their skins4 ,the perception of such unnatural odours would be of no service to worms2 and as such timid creatures would almost certainly exhibit some signs of any new impression1 we may conclude that they did not perceive these odours4 ,the result was different when cabbage-leaves and pieces of onion were employed1 both of which are devoured with much relish by worms4 ,small square pieces of fresh and half-decayed cabbage-leaves and of onion bulbs were on nine occasions buried in my pots1 beneath about of an inch of common garden soil2 and they were always discovered by the worms4 ,one bit of cabbage was discovered and removed in the course of two hours2 three were removed by the next morning1 that is1 after a single night2 two others after two nights2 and the seventh bit after three nights4 ,two pieces of onion were discovered and removed after three nights4 ,bits of fresh raw meat1 of which worms are very fond1 were buried1 and were not discovered within forty-eight hours1 during which time they had not become putrid4 ,the earth above the various buried objects was generally pressed down only slightly1 so as not to prevent the emission of any odour4 ,on two occasions1 however1 the surface was well watered1 and was thus rendered somewhat compact4 ,after the bits of cabbage and onion had been removed1 ,i looked beneath them to see whether the worms had accidentally come up from below1 but there was no sign of a burrow2 and twice the buried objects were laid on pieces of tin-foil which were not in the least displaced4 ,it is of course possible that the worms whilst moving about on the surface of the ground1 with their tails affixed within their burrows1 may have poked their heads into the places where the above objects were buried2 but ,i have never seen worms acting in this manner4 ,some pieces of cabbage-leaf and of onion were twice buried beneath very fine ferruginous sand1 which was slightly pressed down and well watered1 so as to be rendered very compact1 and these pieces were never discovered4 ,on a third occasion the same kind of sand was neither pressed down nor watered1 and the pieces of cabbage were discovered and removed after the second night4 ,these several facts indicate that worms possess some power of smell2 and that they discover by this means odoriferous and much-coveted kinds of food4 ,it may be presumed that all animals which feed on various substances possess the sense of taste1 and this is certainly the case with worms4 ,cabbage-leaves are much liked by worms2 and it appears that they can distinguish between different varieties2 but this may perhaps be owing to differences in their texture4 ,on eleven occasions pieces of the fresh leaves of a common green variety and of the red variety used for pickling were given them1 and they preferred the green1 the red being either wholly neglected or much less gnawed4 ,on two other occasions1 however1 they seemed to prefer the red4 ,half-decayed leaves of the red variety and fresh leaves of the green were attacked about equally4 ,when leaves of the cabbage1 horse-radish 7a favourite food7 and of the onion were given together1 the latter were always1 and manifestly preferred4 ,leaves of the cabbage1 lime-tree1 ,ampelopsis1 parsnip 7,pastinaca71 and celery 7,apium7 were likewise given together2 and those of the celery were first eaten4 ,but when leaves of cabbage1 turnip1 beet1 celery1 wild cherry and carrots were given together1 the two latter kinds1 especially those of the carrot1 were preferred to all the others1 including those of celery4 ,it was also manifest after many trials that wild cherry leaves were greatly preferred to those of the lime-tree and hazel 7,corylus74 ,according to ,mr4 ,bridgman the half-decayed leaves of ,phlox verna are particularly liked by worms4 #ca ,pieces of the leaves of cabbage1 turnip1 horse-radish and onion were left on the pots during #bb days1 and were all attacked and had to be renewed2 but during the whole of this time leaves of an ,artemisia and of the culinary sage1 thyme and mint1 mingled with the above leaves1 were quite neglected excepting those of the mint1 which were occasionally and very slightly nibbled4 ,these latter four kinds of leaves do not differ in texture in a manner which could make them disagreeable to worms2 they all have a strong taste1 but so have the four first mentioned kinds of leaves2 and the wide difference in the result must be attributed to a preference by the worms for one taste over another4 ,mental ,qualities4--,there is little to be said on this head4 ,we have seen that worms are timid4 ,it may be doubted whether they suffer as much pain when injured1 as they seem to express by their contortions4 ,judging by their eagerness for certain kinds of food1 they must enjoy the pleasure of eating4 ,their sexual passion is strong enough to overcome for a time their dread of light4 ,they perhaps have a trace of social feeling1 for they are not disturbed by crawling over each other's bodies1 and they sometimes lie in contact4 ,according to ,hoffmeister they pass the winter either singly or rolled up with others into a ball at the bottom of their burrows4 #cb ,although worms are so remarkably deficient in the several sense-organs1 this does not necessarily preclude intelligence1 as we know from such cases as those of ,laura ,bridgman2 and we have seen that when their attention is engaged1 they neglect impressions to which they would otherwise have attended2 and attention indicates the presence of a mind of some kind4 ,they are also much more easily excited at certain times than at others4 ,they perform a few actions instinctively1 that is1 all the individuals1 including the young1 perform such actions in nearly the same fashion4 ,this is shown by the manner in which the species of ,perichta eject their castings1 so as to construct towers2 also by the manner in which the burrows of the common earth-worm are smoothly lined with fine earth and often with little stones1 and the mouths of their burrows with leaves4 ,one of their strongest instincts is the plugging up the mouths of their burrows with various objects2 and very young worms act in this manner4 ,but some degree of intelligence appears1 as we shall see in the next chapter1 to be exhibited in this work1--a result which has surprised me more than anything else in regard to worms4 ,food and ,digestion4--,worms are omnivorous4 ,they swallow an enormous quantity of earth1 out of which they extract any digestible matter which it may contain2 but to this subject ,i must recur4 ,they also consume a large number of half-decayed leaves of all kinds1 excepting a few which have an unpleasant taste or are too tough for them2 likewise petioles1 peduncles1 and decayed flowers4 ,but they will also consume fresh leaves1 as ,i have found by repeated trials4 ,according to ,morren #cc they will eat particles of sugar and liquorice2 and the worms which ,i kept drew many bits of dry starch into their burrows1 and a large bit had its angles well rounded by the fluid poured out of their mouths4 ,but as they often drag particles of soft stone1 such as of chalk1 into their burrows1 ,i feel some doubt whether the starch was used as food4 ,pieces of raw and roasted meat were fixed several times by long pins to the surface of the soil in my pots1 and night after night the worms could be seen tugging at them1 with the edges of the pieces engulfed in their mouths1 so that much was consumed4 ,raw fat seems to be preferred even to raw meat or to any other substance which was given them1 and much was consumed4 ,they are cannibals1 for the two halves of a dead worm placed in two of the pots were dragged into the burrows and gnawed2 but as far as ,i could judge1 they prefer fresh to putrid meat1 and in so far ,i differ from ,hoffmeister4 ,lon ,fredericq states #cd that the digestive fluid of worms is of the same nature as the pancreatic secretion of the higher animals2 and this conclusion agrees perfectly with the kinds of food which worms consume4 ,pancreatic juice emulsifies fat1 and we have just seen how greedily worms devour fat2 it dissolves fibrin1 and worms eat raw meat2 it converts starch into grape-sugar with wonderful rapidity1 and we shall presently show that the digestive fluid of worms acts on starch4 #ce;a ,but they live chiefly on half-decayed leaves2 and these would be useless to them unless they could digest the cellulose forming the cell-walls2 for it is well known that all other nutritious substances are almost completely withdrawn from leaves1 shortly before they fall off4 ,it has1 however1 now been ascertained that some forms of cellulose1 though very little or not at all attacked by the gastric secretion of the higher animals1 are acted on by that from the pancreas4 #ce;b ,the half-decayed or fresh leaves which worms intend to devour1 are dragged into the mouths of their burrows to a depth of from one to three inches1 and are then moistened with a secreted fluid4 ,it has been assumed that this fluid serves to hasten their decay2 but a large number of leaves were twice pulled out of the burrows of worms and kept for many weeks in a very moist atmosphere under a bell-glass in my study2 and the parts which had been moistened by the worms did not decay more quickly in any plain manner than the other parts4 ,when fresh leaves were given in the evening to worms kept in confinement and examined early on the next morning1 therefore not many hours after they had been dragged into the burrows1 the fluid with which they were moistened1 when tested with neutral litmus paper1 showed an alkaline reaction4 ,this was repeatedly found to be the case with celery1 cabbage and turnip leaves4 ,parts of the same leaves which had not been moistened by the worms1 were pounded with a few drops of distilled water1 and the juice thus extracted was not alkaline4 ,some leaves1 however1 which had been drawn into burrows out of doors1 at an unknown antecedent period1 were tried1 and though still moist1 they rarely exhibited even a trace of alkaline reaction4 ,the fluid1 with which the leaves are bathed1 acts on them whilst they are fresh or nearly fresh1 in a remarkable manner2 for it quickly kills and discolours them4 ,thus the ends of a fresh carrot-leaf1 which had been dragged into a burrow1 were found after twelve hours of a dark brown tint4 ,leaves of celery1 turnip1 maple1 elm1 lime1 thin leaves of ivy1 and1 occasionally those of the cabbage were similarly acted on4 ,the end of a leaf of ,triticum repens1 still attached to a growing plant1 had been drawn into a burrow1 and this part was dark brown and dead1 whilst the rest of the leaf was fresh and green4 ,several leaves of lime and elm removed from burrows out of doors were found affected in different degrees4 ,the first change appears to be that the veins become of a dull reddish-orange4 ,the cells with chlorophyll next lose more or less completely their green colour1 and their contents finally become brown4 ,the parts thus affected often appeared almost black by reflected light2 but when viewed as a transparent object under the microscope1 minute specks of light were transmitted1 and this was not the case with the unaffected parts of the same leaves4 ,these effects1 however1 merely show that the secreted fluid is highly injurious or poisonous to leaves2 for nearly the same effects were produced in from one to two days on various kinds of young leaves1 not only by artificial pancreatic fluid1 prepared with or without thymol1 but quickly by a solution of thymol by itself4 ,on one occasion leaves of ,corylus were much discoloured by being kept for eighteen hours in pancreatic fluid1 without any thymol4 ,with young and tender leaves immersion in human saliva during rather warm weather1 acted in the same manner as the pancreatic fluid1 but not so quickly4 ,the leaves in all these cases often became infiltrated with the fluid4 ,large leaves from an ivy plant growing on a wall were so tough that they could not be gnawed by worms1 but after four days they were affected in a peculiar manner by the secretion poured out of their mouths4 ,the upper surfaces of the leaves1 over which the worms had crawled1 as was shown by the dirt left on them1 were marked in sinuous lines1 by either a continuous or broken chain of whitish and often star-shaped dots1 about #b mm4 in diameter4 ,the appearance thus presented was curiously like that of a leaf1 into which the larva of some minute insect had burrowed4 ,but my son ,francis1 after making and examining sections1 could nowhere find that the cell-walls had been broken down or that the epidermis had been penetrated4 ,when the section passed through the whitish dots1 the grains of chlorophyll were seen to be more or less discoloured1 and some of the palisade and mesophyll cells contained nothing but broken down granular matter4 ,these effects must be attributed to the transudation of the secretion through the epidermis into the cells4 ,the secretion with which worms moisten leaves likewise acts on the starch-granules within the cells4 ,my son examined some leaves of the ash and many of the lime1 which had fallen off the trees and had been partly dragged into worm-burrows4 ,it is known that with fallen leaves the starch-grains are preserved in the guard-cells of the stomata4 ,now in several cases the starch had partially or wholly disappeared from these cells1 in the parts which had been moistened by the secretion2 while it was still well preserved in the other parts of the same leaves4 ,sometimes the starch was dissolved out of only one of the two guard-cells4 ,the nucleus in one case had disappeared1 together with the starch-granules4 ,the mere burying of lime-leaves in damp earth for nine days did not cause the destruction of the starch-granules4 ,on the other hand1 the immersion of fresh lime and cherry leaves for eighteen hours in artificial pancreatic fluid1 led to the dissolution of the starch-granules in the guard-cells as well as in the other cells4 ,from the secretion with which the leaves are moistened being alkaline1 and from its acting both on the starch-granules and on the protoplasmic contents of the cells1 we may infer that it resembles in nature not saliva1 #dj but pancreatic secretion2 and we know from ,fredericq that a secretion of this kind is found in the intestines of worms4 ,as the leaves which are dragged into the burrows are often dry and shrivelled1 it is indispensable for their disintegration by the unarmed mouths of worms that they should first be moistened and softened2 and fresh leaves1 however soft and tender they may be1 are similarly treated1 probably from habit4 ,the result is that they are partially digested before they are taken into the alimentary canal4 ,i am not aware of any other case of extra-stomachal digestion having been recorded4 ,the boa-constrictor is said to bathe its prey with saliva1 but this is doubtful2 and it is done solely for the sake of lubricating its prey4 ,perhaps the nearest analogy may be found in such plants as ,drosera and ,diona2 for here animal matter is digested and converted into peptone not within a stomach1 but on the surfaces of the leaves4 ,calciferous ,glands4--,these glands 7see ,fig4 #a71 judging from their size and from their rich supply of blood-vessels1 must be of much importance to the animal4 ,but almost as many theories have been advanced on their use as there have been observers4 ,they consist of three pairs1 which in the common earth-worm debouch into the alimentary canal in advance of the gizzard1 but posteriorly to it in ,urochta and some other genera4 #da;a ,the two posterior pairs are formed by lamell1 which1 according to ,claparde1 are diverticula from the sophagus4 #da;b ,these lamell are coated with a pulpy cellular layer1 with the outer cells lying free in infinite numbers4 ,if one of these glands is punctured and squeezed1 a quantity of white pulpy matter exudes1 consisting of these free cells4 ,they are minute1 and vary in diameter from #b to #f 4 ,they contain in their centres a little excessively fine granular matter2 but they look so like oil globules that ,claparde and others at first treated them with ether4 ,this produces no effect2 but they are quickly dissolved with effervescence in acetic acid1 and when oxalate of ammonia is added to the solution a white precipitate is thrown down4 ,we may therefore conclude that they contain carbonate of lime4 ,if the cells are immersed in a very little acid1 they become more transparent1 look like ghosts1 and are soon lost to view2 but if much acid is added1 they disappear instantly4 ,after a very large number have been dissolved1 a flocculent residue is left1 which apparently consists of the delicate ruptured cell-walls4 ,in the two posterior pairs of glands the carbonate of lime contained in the cells occasionally aggregates into small rhombic crystals or into concretions1 which lie between the lamell2 but ,i have seen only one case1 and ,claparde only a very few such cases4 ,the two anterior glands differ a little in shape from the four posterior ones1 by being more oval4 ,they differ also conspicuously in generally containing several small1 or two or three larger1 or a single very large concretion of carbonate of lime1 as much as #a mm4 in diameter4 ,when a gland includes only a few very small concretions1 or1 as sometimes happens1 none at all1 it is easily overlooked4 ,the large concretions are round or oval1 and exteriorly almost smooth4 ,one was found which filled up not only the whole gland1 as is often the case1 but its neck2 so that it resembled an olive-oil flask in shape4 ,these concretions when broken are seen to be more or less crystalline in structure4 ,how they escape from the gland is a marvel2 but that they do escape is certain1 for they are often found in the gizzard1 intestines1 and in the castings of worms1 both with those kept in confinement and those in a state of nature4 ,claparde says very little about the structure of the two anterior glands1 and he supposes that the calcareous matter of which the concretions are formed is derived from the four posterior glands4 ,but if an anterior gland which contains only small concretions is placed in acetic acid and afterwards dissected1 or if sections are made of such a gland without being treated with acid1 lamell like those in the posterior glands and coated with cellular matter could be plainly seen1 together with a multitude of free calciferous cells readily soluble in acetic acid4 ,when a gland is completely filled with a single large concretion1 there are no free cells1 as these have been all consumed in forming the concretion4 ,but if such a concretion1 or one of only moderately large size1 is dissolved in acid1 much membranous matter is left1 which appears to consist of the remains of the formerly active lamell4 ,after the formation and expulsion of a large concretion1 new lamell must be developed in some manner4 ,in one section made by my son1 the process had apparently commenced1 although the gland contained two rather large concretions1 for near the walls several cylindrical and oval pipes were intersected1 which were lined with cellular matter and were quite filled with free calciferous cells4 ,a great enlargement in one direction of several oval pipes would give rise to the lamell4 ,besides the free calciferous cells in which no nucleus was visible1 other and rather larger free cells were seen on three occasions2 and these contained a distinct nucleus and nucleolus4 ,they were only so far acted on by acetic acid that the nucleus was thus rendered more distinct4 ,a very small concretion was removed from between two of the lamell within an anterior gland4 ,it was imbedded in pulpy cellular matter1 with many free calciferous cells1 together with a multitude of the larger1 free1 nucleated cells1 and these latter cells were not acted on by acetic acid1 while the former were dissolved4 ,from this and other such cases ,i am led to suspect that the calciferous cells are developed from the larger nucleated ones2 but how this was effected was not ascertained4 ,when an anterior gland contains several minute concretions1 some of these are generally angular or crystalline in outline1 while the greater number are rounded with an irregular mulberry-like surface4 ,calciferous cells adhered to many parts of these mulberry-like masses1 and their gradual disappearance could be traced while they still remained attached4 ,it was thus evident that the concretions are formed from the lime contained within the free calciferous cells4 ,as the smaller concretions increase in size1 they come into contact and unite1 thus enclosing the now functionless lamell2 and by such steps the formation of the largest concretions could be followed4 ,why the process regularly takes place in the two anterior glands1 and only rarely in the four posterior glands1 is quite unknown4 ,morren says that these glands disappear during the winter2 and ,i have seen some instances of this fact1 and others in which either the anterior or posterior glands were at this season so shrunk and empty1 that they could be distinguished only with much difficulty4 ,with respect to the function of the calciferous glands1 it is probable that they primarily serve as organs of excretion1 and secondarily as an aid to digestion4 ,worms consume many fallen leaves2 and it is known that lime goes on accumulating in leaves until they drop off the parent-plant1 instead of being re-absorbed into the stem or roots1 like various other organic and inorganic substances4 #df ,the ashes of a leaf of an acacia have been known to contain as much as #gb per cent4 of lime4 ,worms therefore would be liable to become charged with this earth1 unless there were some special means for its excretion2 and the calciferous glands are well adapted for this purpose4 ,the worms which live in mould close over the chalk1 often have their intestines filled with this substance1 and their castings are almost white4 ,here it is evident that the supply of calcareous matter must be super-abundant4 ,nevertheless with several worms collected on such a site1 the calciferous glands contained as many free calciferous cells1 and fully as many and large concretions1 as did the glands of worms which lived where there was little or no lime2 and this indicates that the lime is an excretion1 and not a secretion poured into the alimentary canal for some special purpose4 ,on the other hand1 the following considerations render it highly probable that the carbonate of lime1 which is excreted by the glands1 aids the digestive process under ordinary circumstances4 ,leaves during their decay generate an abundance of various kinds of acids1 which have been grouped together under the term of humus acids4 ,we shall have to recur to this subject in our fifth chapter1 and ,i need here only say that these acids act strongly on carbonate of lime4 ,the half-decayed leaves which are swallowed in such large quantities by worms would1 therefore1 after they have been moistened and triturated in the alimentary canal1 be apt to produce such acids4 ,and in the case of several worms1 the contents of the alimentary canal were found to be plainly acid1 as shown by litmus paper4 ,this acidity cannot be attributed to the nature of the digestive fluid1 for pancreatic fluid is alkaline2 and we have seen that the secretion which is poured out of the mouths of worms for the sake of preparing the leaves for consumption1 is likewise alkaline4 ,the acidity can hardly be due to uric acid1 as the contents of the upper part of the intestine were often acid4 ,in one case the contents of the gizzard were slightly acid1 those of the upper intestines being more plainly acid4 ,in another case the contents of the pharynx were not acid1 those of the gizzard doubtfully so1 while those of the intestine were distinctly acid at a distance of #e cm4 below the gizzard4 ,even with the higher herbivorous and omnivorous animals1 the contents of the large intestine are acid4 8,this1 however1 is not caused by any acid secretion from the mucous membrane2 the reaction of the intestinal walls in the larger as in the small intestine is alkaline4 ,it must therefore arise from acid fermentations going on in the contents themselves 4 4 4 ,in ,carnivora the contents of the coecum are said to be alkaline1 and naturally the amount of fermentation will depend largely on the nature of the food40 #di ,with worms not only the contents of the intestines1 but their ejected matter or the castings1 are generally acid4 ,thirty castings from different places were tested1 and with three or four exceptions were found to be acid2 and the exceptions may have been due to such castings not having been recently ejected2 for some which were at first acid1 were on the following morning1 after being dried and again moistened1 no longer acid2 and this probably resulted from the humus acids being1 as is known to be the case1 easily decomposed4 ,five fresh castings from worms which lived in mould close over the chalk1 were of a whitish colour and abounded with calcareous matter2 and these were not in the least acid4 ,this shows how effectually carbonate of lime neutralises the intestinal acids4 ,when worms were kept in pots filled with fine ferruginous sand1 it was manifest that the oxide of iron1 with which the grains of silex were coated1 had been dissolved and removed from them in the castings4 ,the digestive fluid of worms resembles in its action1 as already stated1 the pancreatic secretion of the higher animals2 and in these latter1 8pancreatic digestion is essentially alkaline2 the action will not take place unless some alkali be present2 and the activity of an alkaline juice is arrested by acidification1 and hindered by neutralization40 #ej ,therefore it seems highly probable that the innumerable calciferous cells1 which are poured from the four posterior glands into the alimentary canal of worms1 serve to neutralise more or less completely the acids there generated by the half-decayed leaves4 ,we have seen that these cells are instantly dissolved by a small quantity of acetic acid1 and as they do not always suffice to neutralise the contents of even the upper part of the alimentary canal1 the lime is perhaps aggregated into concretions in the anterior pair of glands1 in order that some may be carried down to the posterior parts of the intestine1 where these concretions would be rolled about amongst the acid contents4 ,the concretions found in the intestines and in the castings often have a worn appearance1 but whether this is due to some amount of attrition or of chemical corrosion could not be told4 ,claparde believes that they are formed for the sake of acting as mill-stones1 and of thus aiding in the trituration of the food4 ,they may give some aid in this way2 but ,i fully agree with ,perrier that this must be of quite subordinate importance1 seeing that the object is already attained by stones being generally present in the gizzards and intestines of worms4 ,,chapter ,,ii4 ,,habits ,,of ,,worms--continued4 ,manner in which worms seize objects--,their power of suction--,the instinct of plugging up the mouths of their burrows--,stones piled over the burrows--,the advantages thus gained--,intelligence shown by worms in their manner of plugging up their burrows--,various kinds of leaves and other objects thus used--,triangles of paper--,summary of reasons for believing that worms exhibit some intelligence--,means by which they excavate their burrows1 by pushing away the earth and swallowing it--,earth also swallowed for the nutritious matter which it contains--,depth to which worms burrow1 and the construction of their burrows--,burrows lined with castings1 and in the upper part with leaves--,the lowest part paved with little stones or seeds--,manner in which the castings are ejected--,the collapse of old burrows--,distribution of worms--,tower-like castings in ,bengal--,gigantic castings on the ,nilgiri ,mountains--,castings ejected in all countries4 ,,in the pots in which worms were kept1 leaves were pinned down to the soil1 and at night the manner in which they were seized could be observed4 ,the worms always endeavoured to drag the leaves towards their burrows2 and they tore or sucked off small fragments1 whenever the leaves were sufficiently tender4 ,they generally seized the thin edge of a leaf with their mouths1 between the projecting upper and lower lip2 the thick and strong pharynx being at the same time1 as ,perrier remarks1 pushed forward within their bodies1 so as to afford a point of resistance for the upper lip4 ,in the case of broad flat objects they acted in a wholly different manner4 ,the pointed anterior extremity of the body1 after being brought into contact with an object of this kind1 was drawn within the adjoining rings1 so that it appeared truncated and became as thick as the rest of the body4 ,this part could then be seen to swell a little2 and this1 ,i believe1 is due to the pharynx being pushed a little forwards4 ,then by a slight withdrawal of the pharynx or by its expansion1 a vacuum was produced beneath the truncated slimy end of the body whilst in contact with the object2 and by this means the two adhered firmly together4 #ec ,that under these circumstances a vacuum was produced was plainly seen on one occasion1 when a large worm lying beneath a flaccid cabbage leaf tried to drag it away2 for the surface of the leaf directly over the end of the worm's body became deeply pitted4 ,on another occasion a worm suddenly lost its hold on a flat leaf2 and the anterior end of the body was momentarily seen to be cup-formed4 ,worms can attach themselves to an object beneath water in the same manner2 and ,i saw one thus dragging away a submerged slice of an onion-bulb4 ,the edges of fresh or nearly fresh leaves affixed to the ground were often nibbled by the worms2 and sometimes the epidermis and all the parenchyma on one side was gnawed completely away over a considerable space2 the epidermis alone on the opposite side being left quite clean4 ,the veins were never touched1 and leaves were thus sometimes partly converted into skeletons4 ,as worms have no teeth and as their mouths consist of very soft tissue1 it may be presumed that they consume by means of suction the edges and the parenchyma of fresh leaves1 after they have been softened by the digestive fluid4 ,they cannot attack such strong leaves as those of sea-kale or large and thick leaves of ivy2 though one of the latter after it had become rotten was reduced in parts to the state of a skeleton4 ,worms seize leaves and other objects1 not only to serve as food1 but for plugging up the mouths of their burrows2 and this is one of their strongest instincts4 ,they sometimes work so energetically that ,mr4 ,d4 ,f4 ,simpson1 who has a small walled garden where worms abound in ,bayswater1 informs me that on a calm damp evening he there heard so extraordinary a rustling noise from under a tree from which many leaves had fallen1 that he went out with a light and discovered that the noise was caused by many worms dragging the dry leaves and squeezing them into the burrows4 ,not only leaves1 but petioles of many kinds1 some flower-peduncles1 often decayed twigs of trees1 bits of paper1 feathers1 tufts of wool and horse-hairs are dragged into their burrows for this purpose4 ,i have seen as many as seventeen petioles of a ,clematis projecting from the mouth of one burrow1 and ten from the mouth of another4 ,some of these objects1 such as the petioles just named1 feathers1 c41 are never gnawed by worms4 ,in a gravel-walk in my garden ,i found many hundred leaves of a pine-tree 7,p4 austriaca or nigricans7 drawn by their bases into burrows4 ,the surfaces by which these leaves are articulated to the branches are shaped in as peculiar a manner as is the joint between the leg-bones of a quadruped2 and if these surfaces had been in the least gnawed1 the fact would have been immediately visible1 but there was no trace of gnawing4 ,of ordinary dicotyledonous leaves1 all those which are dragged into burrows are not gnawed4 ,i have seen as many as nine leaves of the lime-tree drawn into the same burrow1 and not nearly all of them had been gnawed2 but such leaves may serve as a store for future consumption4 ,where fallen leaves are abundant1 many more are sometimes collected over the mouth of a burrow than can be used1 so that a small pile of unused leaves is left like a roof over those which have been partly dragged in4 ,a leaf in being dragged a little way into a cylindrical burrow is necessarily much folded or crumpled4 ,when another leaf is drawn in1 this is done exteriorly to the first one1 and so on with the succeeding leaves2 and finally all become closely folded and pressed together4 ,sometimes the worm enlarges the mouth of its burrow1 or makes a fresh one close by1 so as to draw in a still larger number of leaves4 ,they often or generally fill up the interstices between the drawn-in leaves with moist viscid earth ejected from their bodies2 and thus the mouths of the burrows are securely plugged4 ,hundreds of such plugged burrows may be seen in many places1 especially during the autumnal and early winter months4 ,but1 as will hereafter be shown1 leaves are dragged into the burrows not only for plugging them up and for food1 but for the sake of lining the upper part or mouth4 ,when worms cannot obtain leaves1 petioles1 sticks1 c41 with which to plug up the mouths of their burrows1 they often protect them by little heaps of stones2 and such heaps of smooth rounded pebbles may frequently be seen on gravel-walks4 ,here there can be no question about food4 ,a lady1 who was interested in the habits of worms1 removed the little heaps of stones from the mouths of several burrows and cleared the surface of the ground for some inches all round4 ,she went out on the following night with a lantern1 and saw the worms with their tails fixed in their burrows1 dragging the stones inwards by the aid of their mouths1 no doubt by suction4 8,after two nights some of the holes had #h or #i small stones over them2 after four nights one had about #cj1 and another #cd stones40 #eh ,one stone--which had been dragged over the gravel-walk to the mouth of a burrow weighed two ounces2 and this proves how strong worms are4 ,but they show greater strength in sometimes displacing stones in a well-trodden gravel-walk2 that they do so1 may be inferred from the cavities left by the displaced stones being exactly filled by those lying over the mouths of adjoining burrows1 as ,i have myself observed4 ,work of this kind is usually performed during the night2 but ,i have occasionally known objects to be drawn into the burrows during the day4 ,what advantage the worms derive from plugging up the mouths of their burrows with leaves1 c41 or from piling stones over them1 is doubtful4 ,they do not act in this manner at the times when they eject much earth from their burrows2 for their castings then serve to cover the mouths4 ,when gardeners wish to kill worms on a lawn1 it is necessary first to brush or rake away the castings from the surface1 in order that the lime-water may enter the burrows4 #ei;a ,it might be inferred from this fact that the mouths are plugged up with leaves1 c41 to prevent the entrance of water during heavy rain2 but it may be urged against this view that a few1 loose1 well-rounded stones are ill-adapted to keep out water4 ,i have moreover seen many burrows in the perpendicularly cut turf-edgings to gravel-walks1 into which water could hardly flow1 as well plugged as burrows on a level surface4 ,it is not probable that the plugs or piles of stones serve to conceal the burrows from scolopendras1 which1 according to ,hoffmeister1 #ei;b are the bitterest enemies of worms1 or from the larger species of ,carabus and ,staphylinus which attack them ferociously1 for these animals are nocturnal1 and the burrows are opened at night4 ,may not worms when the mouth of the burrow is protected be able to remain with safety with their heads close to it1 which we know that they like to do1 but which costs so many of them their lives8 ,or may not the plugs check the free ingress of the lowest stratum of air1 when chilled by radiation at night1 from the surrounding ground and herbage8 ,i am inclined to believe in this latter view3 firstly1 because when worms were kept in pots in a room with a fire1 in which case cold air could not enter the burrows1 they plugged them up in a slovenly manner2 and secondarily1 because they often coat the upper part of their burrows with leaves1 apparently to prevent their bodies from coming into close contact with the cold damp earth4 ,mr4 ,e4 ,parfitt has suggested to me that the mouths of the burrows are closed in order that the air within them may be kept thoroughly damp1 and this seems the most probable explanation of the habit4 ,but the plugging-up process may serve for all the above purposes4 ,whatever the motive may be1 it appears that worms much dislike leaving the mouths of their burrows open4 ,nevertheless they will reopen them at night1 whether or not they can afterwards close them4 ,numerous open burrows may be seen on recently-dug ground1 for in this case the worms eject their castings in cavities left in the ground1 or in the old burrows instead of piling them over the mouths of their burrows1 and they cannot collect objects on the surface by which the mouths might be protected4 ,so again on a recently disinterred pavement of a ,roman villa at ,abinger 7hereafter to be described7 the worms pertinaciously opened their burrows almost every night1 when these had been closed by being trampled on1 although they were rarely able to find a few minute stones wherewith to protect them4 ,intelligence shown by worms in their manner of plugging up their burrows4--,if a man had to plug up a small cylindrical hole1 with such objects as leaves1 petioles or twigs1 he would drag or push them in by their pointed ends2 but if these objects were very thin relatively to the size of the hole1 he would probably insert some by their thicker or broader ends4 ,the guide in his case would be intelligence4 ,it seemed therefore worth while to observe carefully how worms dragged leaves into their burrows2 whether by their tips or bases or middle parts4 ,it seemed more especially desirable to do this in the case of plants not natives to our country2 for although the habit of dragging leaves into their burrows is undoubtedly instinctive with worms1 yet instinct could not tell them how to act in the case of leaves about which their progenitors knew nothing4 ,if1 moreover1 worms acted solely through instinct or an unvarying inherited impulse1 they would draw all kinds of leaves into their burrows in the same manner4 ,if they have no such definite instinct1 we might expect that chance would determine whether the tip1 base or middle was seized4 ,if both these alternatives are excluded1 intelligence alone is left2 unless the worm in each case first tries many different methods1 and follows that alone which proves possible or the most easy2 but to act in this manner and to try different methods makes a near approach to intelligence4 ,in the first place #bbg withered leaves of various kinds1 mostly of ,english plants1 were pulled out of worm-burrows in several places4 ,of these1 #aha had been drawn into the burrows by or near their tips1 so that the foot-stalk projected nearly upright from the mouth of the burrow2 #bj had been drawn in by their bases1 and in this case the tips projected from the burrows2 and #bf had been seized near the middle1 so that these had been drawn in transversely and were much crumpled4 ,therefore #hj per cent4 7always using the nearest whole number7 had been drawn in by the tip1 #i per cent4 by the base or foot-stalk1 and #aa per cent4 transversely or by the middle4 ,this alone is almost sufficient to show that chance does not determine the manner in which leaves are dragged into the burrows4 ,of the above #bbg leaves1 #gj consisted of the fallen leaves of the common lime-tree1 which is almost certainly not a native of ,england4 ,these leaves are much acuminated towards the tip1 and are very broad at the base with a well-developed foot-stalk4 ,they are thin and quite flexible when half-withered4 ,of the #gj1 #gi per cent4 had been drawn in by or near the tip2 #d per cent4 by or near the base2 and #ag per cent4 transversely or by the middle4 ,these proportions agree very closely1 as far as the tip is concerned1 with those before given4 ,but the percentage drawn in by the base is smaller1 which may be attributed to the breadth of the basal part of the blade4 ,we here1 also1 see that the presence of a foot-stalk1 which it might have been expected would have tempted the worms as a convenient handle1 has little or no influence in determining the manner in which lime leaves are dragged into the burrows4 ,the considerable proportion1 viz41 #ag per cent41 drawn in more or less transversely depends no doubt on the flexibility of these half-decayed leaves4 ,the fact of so many having been drawn in by the middle1 and of some few having been drawn in by the base1 renders it improbable that the worms first tried to draw in most of the leaves by one or both of these methods1 and that they afterwards drew in #gi per cent4 by their tips2 for it is clear that they would not have failed in drawing them in by the base or middle4 ,the leaves of a foreign plant were next searched for1 the blades of which were not more pointed towards the apex than towards the base4 ,this proved to be the case with those of a laburnum 7a hybrid between ,cytisus alpinus and laburnum7 for on doubling the terminal over the basal half1 they generally fitted exactly2 and when there was any difference1 the basal half was a little the narrower4 ,it might1 therefore1 have been expected that an almost equal number of these leaves would have been drawn in by the tip and base1 or a slight excess in favour of the latter4 ,but of #gc leaves 7not included in the first lot of #bbg7 pulled out of worm-burrows1 #fc per cent4 had been drawn in by the tip2 #bg per cent4 by the base1 and #aj per cent4 transversely4 ,we here see that a far larger proportion1 viz41 #bg per cent4 were drawn in by the base than in the case of lime leaves1 the blades of which are very broad at the base1 and of which only #d per cent4 had thus been drawn in4 ,we may perhaps account for the fact of a still larger proportion of the laburnum leaves not having been drawn in by the base1 by worms having acquired the habit of generally drawing in leaves by their tips and thus avoiding the foot-stalk4 ,for the basal margin of the blade in many kinds of leaves forms a large angle with the foot-stalk2 and if such a leaf were drawn in by the foot-stalk1 the basal margin would come abruptly into contact with the ground on each side of the burrow1 and would render the drawing in of the leaf very difficult4 ,nevertheless worms break through their habit of avoiding the foot-stalk1 if this part offers them the most convenient means for drawing leaves into their burrows4 ,the leaves of the endless hybridised varieties of the ,rhododendron vary much in shape2 some are narrowest towards the base and others towards the apex4 ,after they have fallen off1 the blade on each side of the midrib often becomes curled up while drying1 sometimes along the whole length1 sometimes chiefly at the base1 sometimes towards the apex4 ,out of #bh fallen leaves on one bed of peat in my garden1 no less than #bc were narrower in the basal quarter than in the terminal quarter of their length2 and this narrowness was chiefly due to the curling in of the margins4 ,out of #cf fallen leaves on another bed1 in which different varieties of the ,rhododendron grew1 only #ag were narrower towards the base than towards the apex4 ,my son ,william1 who first called my attention to this case1 picked up #bcg fallen leaves in his garden 7where the ,rhododendron grows in the natural soil7 and of these #fe per cent4 could have been drawn by worms into their burrows more easily by the base or foot-stalk than by the tip2 and this was partly due to the shape of the leaf and in a less degree to the curling in of the margins3 #bg per cent4 could have been drawn in more easily by the tip than by the base3 and #h per cent4 with about equal ease by either end4 ,the shape of a fallen leaf ought to be judged of before one end has been drawn into a burrow1 for after this has happened1 the free end1 whether it be the base or apex1 will dry more quickly than the end imbedded in the damp ground2 and the exposed margins of the free end will consequently tend to become more curled inwards than they were when the leaf was first seized by the worm4 ,my son found #ia leaves which had been dragged by worms into their burrows1 though not to a great depth2 of these #ff per cent4 had been drawn in by the base or foot-stalk2 and #cd per cent4 by the tip4 ,in this case1 therefore1 the worms judged with a considerable degree of correctness how best to draw the withered leaves of this foreign plant into their burrows2 notwithstanding that they had to depart from their usual habit of avoiding the foot-stalk4 ,on the gravel-walks in my garden a very large number of leaves of three species of ,pinus 7,p4 austriaca1 nigricans and sylvestris7 are regularly drawn into the mouths of worm burrows4 ,these leaves consist of two so-called needles1 which are of considerable length in the two first and short in the last named species1 and are united to a common base2 and it is by this part that they are almost invariably drawn into the burrows4 ,i have seen only two or at most three exceptions to this rule with worms in a state of nature4 ,as the sharply pointed needles diverge a little1 and as several leaves are drawn into the same burrow1 each tuft forms a perfect chevaux de frise4 ,on two occasions many of these tufts were pulled up in the evening1 but by the following morning fresh leaves had been pulled in1 and the burrows were again well protected4 ,these leaves could not be dragged into the burrows to any depth1 except by their bases1 as a worm cannot seize hold of the two needles at the same time1 and if one alone were seized by the apex1 the other would be pressed against the ground and would resist the entry of the seized one4 ,this was manifest in the above mentioned two or three exceptional cases4 ,in order1 therefore1 that worms should do their work well1 they must drag pine-leaves into their burrows by their bases1 where the two needles are conjoined4 ,but how they are guided in this work is a perplexing question4 ,this difficulty led my son ,francis and myself to observe worms in confinement during several nights by the aid of a dim light1 while they dragged the leaves of the above named pines into their burrows4 ,they moved the anterior extremities of their bodies about the leaves1 and on several occasions when they touched the sharp end of a needle they withdrew suddenly as if pricked4 ,but ,i doubt whether they were hurt1 for they are indifferent to very sharp objects1 and will swallow even rose-thorns and small splinters of glass4 ,it may also be doubted1 whether the sharp ends of the needles serve to tell them that this is the wrong end to seize2 for the points were cut off many leaves for a length of about one inch1 and fifty-seven of them thus treated were drawn into the burrows by their bases1 and not one by the cut-off ends4 ,the worms in confinement often seized the needles near the middle and drew them towards the mouths of their burrows2 and one worm tried in a senseless manner to drag them into the burrow by bending them4 ,they sometimes collected many more leaves over the mouths of their burrows 7as in the case formerly mentioned of lime-leaves7 than could enter them4 ,on other occasions1 however1 they behaved very differently2 for as soon as they touched the base of a pine-leaf1 this was seized1 being sometimes completely engulfed in their mouths1 or a point very near the base was seized1 and the leaf was then quickly dragged or rather jerked into their burrows4 ,it appeared both to my son and myself as if the worms instantly perceived as soon as they had seized a leaf in the proper manner4 ,nine such cases were observed1 but in one of them the worm failed to drag the leaf into its burrow1 as it was entangled by other leaves lying near4 ,in another case a leaf stood nearly upright with the points of the needles partly inserted into a burrow1 but how placed there was not seen2 and then the worm reared itself up and seized the base1 which was dragged into the mouth of the burrow by bowing the whole leaf4 ,on the other hand1 after a worm had seized the base of a leaf1 this was on two occasions relinquished from some unknown motive4 ,as already remarked1 the habit of plugging up the mouths of the burrows with various objects1 is no doubt instinctive in worms2 and a very young one1 born in one of my pots1 dragged for some little distance a ,scotch-fir leaf1 one needle of which was as long and almost as thick as its own body4 ,no species of pine is endemic in this part of ,england1 it is therefore incredible that the proper manner of dragging pine-leaves into the burrows can be instinctive with our worms4 ,but as the worms on which the above observations were made1 were dug up beneath or near some pines1 which had been planted there about forty years1 it was desirable to prove that their actions were not instinctive4 ,accordingly1 pine-leaves were scattered on the ground in places far removed from any pine-tree1 and #ij of them were drawn into the burrows by their bases4 ,only two were drawn in by the tips of the needles1 and these were not real exceptions1 as one was drawn in for a very short distance1 and the two needles of the other cohered4 ,other pine-leaves were given to worms kept in pots in a warm room1 and here the result was different2 for out of #db leaves drawn into the burrows1 no less than #af were drawn in by the tips of the needles4 ,these worms1 however1 worked in a careless or slovenly manner2 for the leaves were often drawn in to only a small depth2 sometimes they were merely heaped over the mouths of the burrows1 and sometimes none were drawn in4 ,i believe that this carelessness may be accounted for either by the warmth of the air1 or by its dampness1 as the pots were covered by glass plates2 the worms consequently did not care about plugging up their holes effectually4 ,pots tenanted by worms and covered with a net which allowed the free entrance of air1 were left out of doors for several nights1 and now #gb leaves were all properly drawn in by their bases4 ,it might perhaps be inferred from the facts as yet given1 that worms somehow gain a general notion of the shape or structure of pine-leaves1 and perceive that it is necessary for them to seize the base where the two needles are conjoined4 ,but the following cases make this more than doubtful4 ,the tips of a large number of needles of ,p4 austriaca were cemented together with shell-lac dissolved in alcohol1 and were kept for some days1 until1 as ,i believe1 all odour or taste had been lost2 and they were then scattered on the ground where no pine-trees grew1 near burrows from which the plugging had been removed4 ,such leaves could have been drawn into the burrows with equal ease by either end2 and judging from analogy and more especially from the case presently to be given of the petioles of ,clematis montana1 ,i expected that the apex would have been preferred4 ,but the result was that out of #aba leaves with the tips cemented1 which were drawn into burrows1 #ajh were drawn in by their bases1 and only #ac by their tips4 ,thinking that the worms might possibly perceive and dislike the smell or taste of the shell-lac1 though this was very improbable1 especially after the leaves had been left out during several nights1 the tips of the needles of many leaves were tied together with fine thread4 ,of leaves thus treated #aej were drawn into burrows--#abc by the base and #bg by the tied tips2 so that between four and five times as many were drawn in by the base as by the tip4 ,it is possible that the short cut-off ends of the thread with which they were tied1 may have tempted the worms to drag in a larger proportional number by the tips than when cement was used4 ,of the leaves with tied and cemented tips taken together 7#bga in number7 #he per cent4 were drawn in by the base and #ae per cent4 by the tips4 ,we may therefore infer that it is not the divergence of the two needles which leads worms in a state of nature almost invariably to drag pine-leaves into their burrows by the base4 ,nor can it be the sharpness of the points of the needles which determines them2 for1 as we have seen1 many leaves with the points cut off were drawn in by their bases4 ,we are thus led to conclude1 that with pine-leaves there must be something attractive to worms in the base1 notwithstanding that few ordinary leaves are drawn in by the base or foot-stalk4 ,petioles4--,we will now turn to the petioles or foot-stalks of compound leaves1 after the leaflets have fallen off4 ,those from ,clematis montana1 which grew over a verandah1 were dragged early in ,january in large numbers into the burrows on an adjoining gravel-walk1 lawn1 and flower-bed4 ,these petioles vary from #b to #d inches in length1 are rigid and of nearly uniform thickness1 except close to the base where they thicken rather abruptly1 being here about twice as thick as in any other part4 ,the apex is somewhat pointed1 but soon withers and is then easily broken off4 ,of these petioles1 #cad were pulled out of burrows in the above specified sites2 and it was found that #gf per cent4 had been drawn in by their tips1 and #bd per cent by their bases2 so that those drawn in by the tip were a little more than thrice as many as those drawn in by the base4 ,some of those extracted from the well-beaten gravel-walk were kept separate from the others2 and of these 7#ei in number7 nearly five times as many had been drawn in by the tip as by the base2 whereas of those extracted from the lawn and flower-bed1 where from the soil yielding more easily1 less care would be necessary in plugging up the burrows1 the proportion of those drawn in by the tip 7#acj7 to those drawn in by the base 7#dh7 was rather less than three to one4 ,that these petioles had been dragged into the burrows for plugging them up1 and not for food1 was manifest1 as neither end1 as far as ,i could see1 had been gnawed4 ,as several petioles are used to plug up the same burrow1 in one case as many as #aj1 and in another case as many as #ae1 the worms may perhaps at first draw in a few by the thicker end so as to save labour2 but afterwards a large majority are drawn in by the pointed end1 in order to plug up the hole securely4 ,the fallen petioles of our native ash-tree were next observed1 and the rule with most objects1 viz41 that a large majority are dragged into the burrows by the more pointed end1 had not here been followed2 and this fact much surprised me at first4 ,these petioles vary in length from #e to #h inches2 they are thick and fleshy towards the base1 whence they taper gently towards the apex1 which is a little enlarged and truncated where the terminal leaflet had been originally attached4 ,under some ash-trees growing in a grass-field1 #bbi petioles were pulled out of worm burrows early in ,january1 and of these #ea4e per cent4 had been drawn in by the base1 and #dh4e per cent4 by the apex4 ,this anomaly was however readily explained as soon as the thick basal part was examined2 for in #gh out of #ajc petioles1 this part had been gnawed by worms1 just above the horse-shoe shaped articulation4 ,in most cases there could be no mistake about the gnawing2 for ungnawed petioles which were examined after being exposed to the weather for eight additional weeks had not become more disintegrated or decayed near the base than elsewhere4 ,it is thus evident that the thick basal end of the petiole is drawn in not solely for the sake of plugging up the mouths of the burrows1 but as food4 ,even the narrow truncated tips of some few petioles had been gnawed2 and this was the case in #f out of #cg which were examined for this purpose4 ,worms1 after having drawn in and gnawed the basal end1 often push the petioles out of their burrows2 and then drag in fresh ones1 either by the base for food1 or by the apex for plugging up the mouth more effectually4 ,thus1 out of #cg petioles inserted by their tips1 #e had been previously drawn in by the base1 for this part had been gnawed4 ,again1 ,i collected a handful of petioles lying loose on the ground close to some plugged-up burrows1 where the surface was thickly strewed with other petioles which apparently had never been touched by worms2 and #ad out of #dg 7i4e4 nearly one-third71 after having had their bases gnawed had been pushed out of the burrows and were now lying on the ground4 ,from these several facts we may conclude that worms draw in some petioles of the ash by the base to serve as food1 and others by the tip to plug up the mouths of their burrows in the most efficient manner4 ,the petioles of ,robinia pseudo-acacia vary from #d or #e to nearly #ab inches in length2 they are thick close to the base before the softer parts have rotted off1 and taper much towards the upper end4 ,they are so flexible that ,i have seen some few doubled up and thus drawn into the burrows of worms4 ,unfortunately these petioles were not examined until ,february1 by which time the softer parts had completely rotted off1 so that it was impossible to ascertain whether worms had gnawed the bases1 though this is in itself probable4 ,out of #aba petioles extracted from burrows early in ,february1 #fh were imbedded by the base1 and #ec by the apex4 ,on ,february #e all the petioles which had been drawn into the burrows beneath a ,robinia1 were pulled up2 and after an interval of eleven days1 #ce petioles had been again dragged in1 #ai by the base1 and #af by the apex4 ,taking these two lots together1 #ef per cent4 were drawn in by the base1 and #dd per cent4 by the apex4 ,as all the softer parts had long ago rotted off1 we may feel sure1 especially in the latter case1 that none had been drawn in as food4 ,at this season1 therefore1 worms drag these petioles into their burrows indifferently by either end1 a slight preference being given to the base4 ,this latter fact may be accounted for by the difficulty of plugging up a burrow with objects so extremely thin as are the upper ends4 ,in support of this view1 it may be stated that out of the #af petioles which had been drawn in by their upper ends1 the more attenuated terminal portion of #g had been previously broken off by some accident4 ,triangles of paper4--,elongated triangles were cut out of moderately stiff writing-paper1 which was rubbed with raw fat on both sides1 so as to prevent their becoming excessively limp when exposed at night to rain and dew4 ,the sides of all the triangles were three inches in length1 with the bases of #abj one inch1 and of the other #ahc half an inch in length4 ,these latter triangles were very narrow or much acuminated4 #gi ,as a check on the observations presently to be given1 similar triangles in a damp state were seized by a very narrow pair of pincers at different points and at all inclinations with reference to the margins1 and were then drawn into a short tube of the diameter of a worm-burrow4 ,if seized by the apex1 the triangle was drawn straight into the tube1 with its margins infolded2 if seized at some little distance from the apex1 for instance at half an inch1 this much was doubled back within the tube4 ,so it was with the base and basal angles1 though in this case the triangles offered1 as might have been expected1 much more resistance to being drawn in4 ,if seized near the middle the triangle was doubled up1 with the apex and base left sticking out of the tube4 ,as the sides of the triangles were three inches in length1 the result of their being drawn into a tube or into a burrow in different ways1 may be conveniently divided into three groups3 those drawn in by the apex or within an inch of it2 those drawn in by the base or within an inch of it2 and those drawn in by any point in the middle inch4 ,in order to see how the triangles would be seized by worms1 some in a damp state were given to worms kept in confinement4 ,they were seized in three different manners in the case of both the narrow and broad triangles3 viz41 by the margin2 by one of the three angles1 which was often completely engulfed in their mouths2 and lastly1 by suction applied to any part of the flat surface4 ,if lines parallel to the base and an inch apart1 are drawn across a triangle with the sides three inches in length1 it will be divided into three parts of equal length4 ,now if worms seized indifferently by chance any part1 they would assuredly seize on the basal part or division far oftener than on either of the two other divisions4 ,for the area of the basal to the apical part is as #e to #a1 so that the chance of the former being drawn into a burrow by suction1 will be as #e to #a1 compared with the apical part4 ,the base offers two angles and the apex only one1 so that the former would have twice as good a chance 7independently of the size of the angles7 of being engulfed in a worm's mouth1 as would the apex4 ,it should1 however1 be stated that the apical angle is not often seized by worms2 the margin at a little distance on either side being preferred4 ,i judge of this from having found in #dj out of #df cases in which triangles had been drawn into burrows by their apical ends1 that the tip had been doubled back within the burrow for a length of between #a_/bj of an inch and #a inch4 ,lastly1 the proportion between the margins of the basal and apical parts is as #c to #b for the broad1 and #b to #b for the narrow triangles4 ,from these several considerations it might certainly have been expected1 supposing that worms seized hold of the triangles by chance1 that a considerably larger proportion would have been dragged into the burrows by the basal than by the apical part2 but we shall immediately see how different was the result4 ,triangles of the above specified sizes were scattered on the ground in many places and on many successive nights near worm-burrows1 from which the leaves1 petioles1 twigs1 c41 with which they had been plugged1 were removed4 ,altogether #cjc triangles were drawn by worms into their burrows3 #ab others were drawn in by both ends1 but as it was impossible to judge by which end they had been first seized1 these are excluded4 ,of the #cjc1 #fb per cent4 had been drawn in by the apex 7using this term for all drawn in by the apical part1 one inch in length72 #ae per cent4 by the middle2 and #bc per cent4 by the basal part4 ,if they had been drawn indifferently by any point1 the proportion for the apical1 middle and basal parts would have been #cc4c per cent4 for each2 but1 as we have just seen1 it might have been expected that a much larger proportion would have been drawn in by the basal than by any other part4 ,as the case stands1 nearly three times as many were drawn in by the apex as by the base4 ,if we consider the broad triangles by themselves1 #ei per cent4 were drawn in by the apex1 #be per cent4 by the middle1 and #af per cent4 by the base4 ,of the narrow triangles1 #fe per cent4 were drawn in by the apex1 #ad per cent1 by the middle1 and #ba per cent4 by the base2 so that here those drawn in by the apex were more than #c times as many as those drawn in by the base4 ,we may therefore conclude that the manner in which the triangles are drawn into the burrows is not a matter of chance4 ,in eight cases1 two triangles had been drawn into the same burrow1 and in seven of these cases1 one had been drawn in by the apex and the other by the base4 ,this again indicates that the result is not determined by chance4 ,worms appear sometimes to revolve in the act of drawing in the triangles1 for five out of the whole lot had been wound into an irregular spire round the inside of the burrow4 ,worms kept in a warm room drew #fc triangles into their burrows2 but1 as in the case of the pine-leaves1 they worked in a rather careless manner1 for only #dd per cent4 were drawn in by the apex1 #bb per cent4 by the middle1 and #cc per cent4 by the base4 ,in five cases1 two triangles were drawn into the same burrow4 ,it may be suggested with much apparent probability that so large a proportion of the triangles were drawn in by the apex1 not from the worms having selected this end as the most convenient for the purpose1 but from having first tried in other ways and failed4 ,this notion was countenanced by the manner in which worms in confinement were seen to drag about and drop the triangles2 but then they were working carelessly4 ,i did not at first perceive the importance of this subject1 but merely noticed that the bases of those triangles which had been drawn in by the apex1 were generally clean and not crumpled4 ,the subject was afterwards attended to carefully4 ,in the first place several triangles which had been drawn in by the basal angles1 or by the base1 or a little above the base1 and which were thus much crumpled and dirtied1 were left for some hours in water and were then well shaken while immersed2 but neither the dirt nor the creases were thus removed4 ,only slight creases could be obliterated1 even by pulling the wet triangles several times through my fingers4 ,owing to the slime from the worms' bodies1 the dirt was not easily washed off4 ,we may therefore conclude that if a triangle1 before being dragged in by the apex1 had been dragged into a burrow by its base with even a slight degree of force1 the basal part would long retain its creases and remain dirty4 ,the condition of #hi triangles 7#fe narrow and #bd broad ones71 which had been drawn in by the apex1 was observed2 and the bases of only #g of them were at all creased1 being at the same time generally dirty4 ,of the #hb uncreased triangles1 #ad were dirty at the base2 but it does not follow from this fact that these had first been dragged towards the burrows by their bases2 for the worms sometimes covered large portions of the triangles with slime1 and these when dragged by the apex over the ground would be dirtied2 and during rainy weather1 the triangles were often dirtied over one whole side or over both sides4 ,if the worms had dragged the triangles to the mouths of their burrows by their bases1 as often as by their apices1 and had then perceived1 without actually trying to draw them into the burrow1 that the broader end was not well adapted for this purpose--even in this case a large proportion would probably have had their basal ends dirtied4 ,we may therefore infer--improbable as is the inference--that worms are able by some means to judge which is the best end by which to draw triangles of paper into their burrows4 ,the percentage results of the foregoing observations on the manner in which worms draw various kinds of objects into the mouths of their burrows may be abridged as follows3-- ,nature of ,drawn into the ,drawn in1 by or ,drawn in1 by or ,object4 burrows1 by or near the near the base4 near the apex4 middle4 ,leaves of #hj #aa #i various kinds --of the ,lime1 #gi #ag #d basal margin of blade broad1 apex acuminated --of a ,laburnum1 #fc #aj #bg basal part of blade as narrow as1 or sometimes little narrower than the apical part --of the #cd 444 #ff ,rhododendron1 basal part of blade often narrower than the apical part --of ,pine-trees1 444 444 #ajj consisting of two needles arising from a common base ,petioles of a #gf 444 #bd ,clematis1 somewhat pointed at the apex1 and blunt at the base --of the ,ash1 #dh4e 444 #ea4e the thick basal end often drawn in to serve as food --of ,robinia1 #dd 444 #ef extremely thin1 especially towards the apex1 so as to be ill-fitted for plugging up the burrows ,triangles of #fb #ae #bc paper1 of the two sizes --of the broad #ei #be #af ones alone --of the narrow #fe #ad #ba ones alone ,if we consider these several cases1 we can hardly escape from the conclusion that worms show some degree of intelligence in their manner of plugging up their burrows4 ,each particular object is seized in too uniform a manner1 and from causes which we can generally understand1 for the result to be attributed to mere chance4 ,that every object has not been drawn in by its pointed end1 may be accounted for by labour having been saved through some being inserted by their broader or thicker ends4 ,no doubt worms are led by instinct to plug up their burrows2 and it might have been expected that they would have been led by instinct how best to act in each particular case1 independently of intelligence4 ,we see how difficult it is to judge whether intelligence comes into play1 for even plants might sometimes be thought to be thus directed2 for instance when displaced leaves re-direct their upper surfaces towards the light by extremely complicated movements and by the shortest course4 ,with animals1 actions appearing due to intelligence may be performed through inherited habit without any intelligence1 although aboriginally thus acquired4 ,or the habit may have been acquired through the preservation and inheritance of beneficial variations of some other habit2 and in this case the new habit will have been acquired independently of intelligence throughout the whole course of its development4 ,there is no priori improbability in worms having acquired special instincts through either of these two latter means4 ,nevertheless it is incredible that instincts should have been developed in reference to objects1 such as the leaves of petioles of foreign plants1 wholly unknown to the progenitors of the worms which act in the described manner4 ,nor are their actions so unvarying or inevitable as are most true instincts4 ,as worms are not guided by special instincts in each particular case1 though possessing a general instinct to plug up their burrows1 and as chance is excluded1 the next most probable conclusion seems to be that they try in many different ways to draw in objects1 and at last succeed in some one way4 ,but it is surprising that an animal so low in the scale as a worm should have the capacity for acting in this manner1 as many higher animals have no such capacity4 ,for instance1 ants may be seen vainly trying to drag an object transversely to their course1 which could be easily drawn longitudinally2 though after a time they generally act in a wiser manner1 ,m4 ,fabre states #hi;a that a ,sphex--an insect belonging to the same highly-endowed order with ants--stocks its nest with paralysed grass-hoppers1 which are invariably dragged into the burrow by their antenn4 ,when these were cut off close to the head1 the ,sphex seized the palpi2 but when these were likewise cut off1 the attempt to drag its prey into the burrow was given up in despair4 ,the ,sphex had not intelligence enough to seize one of the six legs or the ovipositor of the grasshopper1 which1 as ,m4 ,fabre remarks1 would have served equally well4 ,so again1 if the paralysed prey with an egg attached to it be taken out of the cell1 the ,sphex after entering and finding the cell empty1 nevertheless closes it up in the usual elaborate manner4 ,bees will try to escape and go on buzzing for hours on a window1 one half of which has been left open4 ,even a pike continued during three months to dash and bruise itself against the glass sides of an aquarium1 in the vain attempt to seize minnows on the opposite side4 #hi;b ,a cobra-snake was seen by ,mr4 ,layard #ij to act much more wisely than either the pike or the ,sphex2 it had swallowed a toad lying within a hole1 and could not withdraw its head2 the toad was disgorged1 and began to crawl away2 it was again swallowed and again disgorged2 and now the snake had learnt by experience1 for it seized the toad by one of its legs and drew it out of the hole4 ,the instincts of even the higher animals are often followed in a senseless or purposeless manner3 the weaver-bird will perseveringly wind threads through the bars of its cage1 as if building a nest3 a squirrel will pat nuts on a wooden floor1 as if he had just buried them in the ground3 a beaver will cut up logs of wood and drag them about1 though there is no water to dam up2 and so in many other cases4 ,mr4 ,romanes1 who has specially studied the minds of animals1 believes that we can safely infer intelligence1 only when we see an individual profiting by its own experience4 ,by this test the cobra showed some intelligence2 but this would have been much plainer if on a second occasion he had drawn a toad out of a hole by its leg4 ,the ,sphex failed signally in this respect4 ,now if worms try to drag objects into their burrows first in one way and then in another1 until they at last succeed1 they profit1 at least in each particular instance1 by experience4 ,but evidence has been advanced showing that worms do not habitually try to draw objects into their burrows in many different ways4 ,thus half-decayed lime-leaves from their flexibility could have been drawn in by their middle or basal parts1 and were thus drawn into the burrows in considerable numbers2 yet a large majority were drawn in by or near the apex4 ,the petioles of the ,clematis could certainly have been drawn in with equal ease by the base and apex2 yet three times and in certain cases five times as many were drawn in by the apex as by the base4 ,it might have been thought that the foot-stalks of leaves would have tempted the worms as a convenient handle2 yet they are not largely used1 except when the base of the blade is narrower than the apex4 ,a large number of the petioles of the ash are drawn in by the base2 but this part serves the worms as food4 ,in the case of pine-leaves worms plainly show that they at least do not seize the leaf by chance2 but their choice does not appear to be determined by the divergence of the two needles1 and the consequent advantage or necessity of drawing them into their burrows by the base4 ,with respect to the triangles of paper1 those which had been drawn in by the apex rarely had their bases creased or dirty2 and this shows that the worms had not often first tried to drag them in by this end4 ,if worms are able to judge1 either before drawing or after having drawn an object close to the mouths of their burrows1 how best to drag it in1 they must acquire some notion of its general shape4 ,this they probably acquire by touching it in many places with the anterior extremity of their bodies1 which serves as a tactile organ4 ,it may be well to remember how perfect the sense of touch becomes in a man when born blind and deaf1 as are worms4 ,if worms have the power of acquiring some notion1 however rude1 of the shape of an object and of their burrows1 as seems to be the case1 they deserve to be called intelligent2 for they then act in nearly the same manner as would a man under similar circumstances4 ,to sum up1 as chance does not determine the manner in which objects are drawn into the burrows1 and as the existence of specialized instincts for each particular case cannot be admitted1 the first and most natural supposition is that worms try all methods until they at last succeed2 but many appearances are opposed to such a supposition4 ,one alternative alone is left1 namely1 that worms1 although standing low in the scale of organization1 possess some degree of intelligence4 ,this will strike every one as very improbable2 but it may be doubted whether we know enough about the nervous system of the lower animals to justify our natural distrust of such a conclusion4 ,with respect to the small size of the cerebral ganglia1 we should remember what a mass of inherited knowledge1 with some power of adapting means to an end1 is crowded into the minute brain of a worker-ant4 ,means by which worms excavate their burrows4--,this is effected in two ways2 by pushing away the earth on all sides1 and by swallowing it4 ,in the former case1 the worm inserts the stretched out and attenuated anterior extremity of its body into any little crevice1 or hole2 and then1 as ,perrier remarks1 #ic the pharynx is pushed forwards into this part1 which consequently swells and pushes away the earth on all sides4 ,the anterior extremity thus serves as a wedge4 ,it also serves1 as we have before seen1 for prehension and suction1 and as a tactile organ4 ,a worm was placed on loose mould1 and it buried itself in between two and three minutes4 ,on another occasion four worms disappeared in #ae minutes between the sides of the pot and the earth1 which had been moderately pressed down4 ,on a third occasion three large worms and a small one were placed on loose mould well mixed with fine sand and firmly pressed down1 and they all disappeared1 except the tail of one1 in #ce minutes4 ,on a fourth occasion six large worms were placed on argillaceous mud mixed with sand firmly pressed down1 and they disappeared1 except the extreme tips of the tails of two of them1 in #dj minutes4 ,in none of these cases1 did the worms swallow1 as far as could be seen1 any earth4 ,they generally entered the ground close to the sides of the pot4 ,a pot was next filled with very fine ferruginous sand1 which was pressed down1 well watered1 and thus rendered extremely compact4 ,a large worm left on the surface did not succeed in penetrating it for some hours1 and did not bury itself completely until #be hrs4 #dj min4 had elapsed4 ,this was effected by the sand being swallowed1 as was evident by the large quantity ejected from the vent1 long before the whole body had disappeared4 ,castings of a similar nature continued to be ejected from the burrow during the whole of the following day4 ,as doubts have been expressed by some writers whether worms ever swallow earth solely for the sake of making their burrows1 some additional cases may be given4 ,a mass of fine reddish sand1 #bc inches in thickness1 left on the ground for nearly two years1 had been penetrated in many places by worms2 and their castings consisted partly of the reddish sand and partly of black earth brought up from beneath the mass4 ,this sand had been dug up from a considerable depth1 and was of so poor a nature that weeds could not grow on it4 ,it is therefore highly improbable that it should have been swallowed by the worms as food4 ,again in a field near my house the castings frequently consist of almost pure chalk1 which lies at only a little depth beneath the surface2 and here again it is very improbable that the chalk should have been swallowed for the sake of the very little organic matter which could have percolated into it from the poor overlying pasture4 ,lastly1 a casting thrown up through the concrete and decayed mortar between the tiles1 with which the now ruined aisle of ,beaulieu ,abbey had formerly been paved1 was washed1 so that the coarser matter alone was left4 ,this consisted of grains of quartz1 micaceous slate1 other rocks1 and bricks or tiles1 many of them from #a_/bj to #a_/aj inch in diameter4 ,no one will suppose that these grains were swallowed as food1 yet they formed more than half of the casting1 for they weighed #ai grains1 the whole casting having weighed #cc grains4 ,whenever a worm burrows to a depth of some feet in undisturbed compact ground1 it must form its passage by swallowing the earth2 for it is incredible that the ground could yield on all sides to the pressure of the pharynx when pushed forwards within the worm's body4 ,that worms swallow a larger quantity of earth for the sake of extracting any nutritious matter which it may contain than for making their burrows1 appears to me certain4 ,but as this old belief has been doubted by so high an authority as ,claparde1 evidence in its favour must be given in some detail4 ,there is no priori improbability in such a belief1 for besides other annelids1 especially the ,arenicola marina1 which throws up such a profusion of castings on our tidal sands1 and which it is believed thus subsists1 there are animals belonging to the most distinct classes1 which do not burrow1 but habitually swallow large quantities of sand2 namely1 the molluscan ,onchidium and many ,echinoderms4 #ig ,if earth were swallowed only when worms deepened their burrows or made new ones1 castings would be thrown up only occasionally2 but in many places fresh castings may be seen every morning1 and the amount of earth ejected from the same burrow on successive days is large4 ,yet worms do not burrow to a great depth1 except when the weather is very dry or intensely cold4 ,on my lawn the black vegetable mould or humus is only about #e inches in thickness1 and overlies light-coloured or reddish clayey soil3 now when castings are thrown up in the greatest profusion1 only a small proportion are light coloured1 and it is incredible that the worms should daily make fresh burrows in every direction in the thin superficial layer of dark-coloured mould1 unless they obtained nutriment of some kind from it4 ,i have observed a strictly analogous case in a field near my house where bright red clay lay close beneath the surface4 ,again on one part of the ,downs near ,winchester the vegetable mould overlying the chalk was found to be only from #c to #d inches in thickness2 and the many castings here ejected were as black as ink and did not effervesce with acids2 so that the worms must have confined themselves to this thin superficial layer of mould1 of which large quantities were daily swallowed4 ,in another place at no great distance the castings were white2 and why the worms should have burrowed into the chalk in some places and not in others1 ,i am unable to conjecture4 ,two great piles of leaves had been left to decay in my grounds1 and months after their removal1 the bare surface1 several yards in diameter1 was so thickly covered during several months with castings that they formed an almost continuous layer2 and the large number of worms which lived here must have subsisted during these months on nutritious matter contained in the black earth4 ,the lowest layer from another pile of decayed leaves mixed with some earth was examined under a high power1 and the number of spores of various shapes and sizes which it contained was astonishingly great2 and these crushed in the gizzards of worms may largely aid in supporting them4 ,whenever castings are thrown up in the greatest number1 few or no leaves are drawn into the burrows2 for instance the turf along a hedgerow1 about #bjj yards in length1 was daily observed in the autumn during several weeks1 and every morning many fresh castings were seen2 but not a single leaf was drawn into these burrows4 ,these castings from their blackness and from the nature of the subsoil could not have been brought up from a greater depth than #f or #h inches4 ,on what could these worms have subsisted during this whole time1 if not on matter contained in the black earth8 ,on the other hand1 whenever a large number of leaves are drawn into the burrows1 the worms seem to subsist chiefly on them1 for few earth-castings are then ejected on the surface4 ,this difference in the behaviour of worms at different times1 perhaps explains a statement by ,claparde1 namely1 that triturated leaves and earth are always found in distinct parts of their intestines4 ,worms sometimes abound in places where they can rarely or never obtain dead or living leaves2 for instance1 beneath the pavement in well-swept courtyards1 into which leaves are only occasionally blown4 ,my son ,horace examined a house1 one corner of which had subsided2 and he found here in the cellar1 which was extremely damp1 many small worm-castings thrown up between the stones with which the cellar was paved2 and in this case it is improbable that the worms could ever have obtained leaves4 ,mr4 ,a4 ,c4 ,horner confirms this account1 as he has seen castings in the cellars of his house1 which is an old one at ,tonbridge4 ,but the best evidence1 known to me1 of worms subsisting for at least considerable periods of time solely on the organic matter contained in earth1 is afforded by some facts communicated to me by ,dr4 ,king4 ,near ,nice large castings abound in extraordinary numbers1 so that #e or #f were often found within the space of a square foot4 ,they consist of fine1 pale-coloured earth1 containing calcareous matter1 which after having passed through the bodies of worms and being dried1 coheres with considerable force4 ,i have reason to believe that these castings had been formed by species of ,perichta1 which have been naturalized here from the ,east4 #aja ,they rise like towers1 with their summits often a little broader than their bases1 sometimes to a height of above #c and often to a height of #b inches4 ,the tallest of those which were measured was #c4c inches in height and #a inch in diameter4 ,a small cylindrical passage runs up the centre of each tower1 through which the worm ascends to eject the earth which it has swallowed1 and thus to add to its height4 ,a structure of this kind would not allow leaves being easily dragged from the surrounding ground into the burrows2 and ,dr4 ,king1 who looked carefully1 never saw even a fragment of a leaf thus drawn in4 ,nor could any trace be discovered of the worms having crawled down the exterior surfaces of the towers in search of leaves2 and had they done so1 tracks would almost certainly have been left on the upper part whilst it remained soft4 ,it does not1 however1 follow that these worms do not draw leaves into their burrows during some other season of the year1 at which time they would not build up their towers4 ,from the several foregoing cases1 it can hardly be doubted that worms swallow earth1 not only for the sake of making their burrows1 but for obtaining food4 ,hensen1 however1 concludes from his analyses of mould that worms probably could not live on ordinary vegetable mould1 though he admits that they might be nourished to some extent by leaf-mould4 #ajb ,but we have seen that worms eagerly devour raw meat1 fat1 and dead worms2 and ordinary mould can hardly fail to contain many ova1 larv1 and small living or dead creatures1 spores of cryptogamic plants1 and micrococci1 such as those which give rise to saltpetre4 ,these various organisms1 together with some cellulose from any leaves and roots not utterly decayed1 might well account for such large quantities of mould being swallowed by worms4 ,it may be worth while here to recall the fact that certain species of ,utricularia1 which grow in damp places in the tropics1 possess bladders beautifully constructed for catching minute subterranean animals2 and these traps would not have been developed unless many small animals inhabited such soil4 ,the depth to which worms penetrate1 and the construction of their burrows4--,although worms usually live near the surface1 yet they burrow to a considerable depth during long-continued dry weather and severe cold4 ,in ,scandinavia1 according to ,eisen1 and in ,scotland1 according to ,mr4 ,lindsay ,carnagie1 the burrows run down to a depth of from #g to #h feet2 in ,north ,germany1 according to ,hoffmeister1 from #f to #h feet1 but ,hensen says1 from #c to #f feet4 ,this latter observer has seen worms frozen at a depth of #a feet beneath the surface4 ,i have not myself had many opportunities for observation1 but ,i have often met with worms at depths of #c to #d feet4 ,in a bed of fine sand overlying the chalk1 which had never been disturbed1 a worm was cut into two at #ee inches1 and another was found here at ,down in ,december at the bottom of its burrow1 at #fa inches beneath the surface4 ,lastly1 in earth near an old ,roman ,villa1 which had not been disturbed for many centuries1 a worm was met with at a depth of #ff inches2 and this was in the middle of ,august4 ,the burrows run down perpendicularly1 or more commonly a little obliquely4 ,they are said sometimes to branch1 but as far as ,i have seen this does not occur1 except in recently dug ground and near the surface4 ,they are generally1 or as ,i believe invariably1 lined with a thin layer of fine1 dark-coloured earth voided by the worms2 so that they must at first be made a little wider than their ultimate diameter4 ,i have seen several burrows in undisturbed sand thus lined at a depth of #d ft4 #f in42 and others close to the surface thus lined in recently dug ground4 ,the walls of fresh burrows are often dotted with little globular pellets of voided earth1 still soft and viscid2 and these1 as it appears1 are spread out on all sides by the worm as it travels up or down its burrow4 ,the lining thus formed becomes very compact and smooth when nearly dry1 and closely fits the worm's body4 ,the minute reflexed bristles which project in rows on all sides from the body1 thus have excellent points of support2 and the burrow is rendered well adapted for the rapid movement of the animal4 ,the lining appears also to strengthen the walls1 and perhaps saves the worm's body from being scratched4 ,i think so because several burrows which passed through a layer of sifted coal-cinders1 spread over turf to a thickness of #a inch1 had been thus lined to an unusual thickness4 ,in this case the worms1 judging from the castings1 had pushed the cinders away on all sides and had not swallowed any of them4 ,in another place1 burrows similarly lined1 passed through a layer of coarse coal-cinders1 #c inches in thickness4 ,we thus see that the burrows are not mere excavations1 but may rather be compared with tunnels lined with cement4 ,the mouths of the burrow are in addition often lined with leaves2 and this is an instinct distinct from that of plugging them up1 and does not appear to have been hitherto noticed4 ,many leaves of the ,scotch-fir or pine 7,pinus sylvestris7 were given to worms kept in confinement in two pots2 and when after several weeks the earth was carefully broken up1 the upper parts of three oblique burrows were found surrounded for lengths of #g1 #d1 and #c inches with pine-leaves1 together with fragments of other leaves which had been given the worms as food4 ,glass beads and bits of tile1 which had been strewed on the surface of the soil1 were stuck into the interstices between the pine-leaves2 and these interstices were likewise plastered with the viscid castings voided by the worms4 ,the structures thus formed cohered so well1 that ,i succeeded in removing one with only a little earth adhering to it4 ,it consisted of a slightly curved cylindrical case1 the interior of which could be seen through holes in the sides and at either end4 ,the pine-leaves had all been drawn in by their bases2 and the sharp points of the needles had been pressed into the lining of voided earth4 ,had this not been effectually done1 the sharp points would have prevented the retreat of the worms into their burrows2 and these structures would have resembled traps armed with converging points of wire1 rendering the ingress of an animal easy and its egress difficult or impossible4 ,the skill shown by these worms is noteworthy and is the more remarkable1 as the ,scotch pine is not a native of this district4 ,after having examined these burrows made by worms in confinement1 ,i looked at those in a flower-bed near some ,scotch pines4 ,these had all been plugged up in the ordinary manner with the leaves of this tree1 drawn in for a length of from #a to #a inch2 but the mouths of many of them were likewise lined with them1 mingled with fragments of other kinds of leaves1 drawn in to a depth of #d or #e inches4 ,worms often remain1 as formerly stated1 for a long time close to the mouths of their burrows1 apparently for warmth2 and the basket-like structures formed of leaves would keep their bodies from coming into close contact with the cold damp earth4 ,that they habitually rested on the pine-leaves1 was rendered probable by their clean and almost polished surfaces4 ,the burrows which run far down into the ground1 generally1 or at least often1 terminate in a little enlargement or chamber4 ,here1 according to ,hoffmeister1 one or several worms pass the winter rolled up into a ball4 ,mr4 ,lindsay ,carnagie informed me 7#ahch7 that he had examined many burrows over a stone-quarry in ,scotland1 where the overlying boulder-clay and mould had recently been cleared away1 and a little vertical cliff thus left4 ,in several cases the same burrow was a little enlarged at two or three points one beneath the other2 and all the burrows terminated in a rather large chamber1 at a depth of #g or #h feet from the surface4 ,these chambers contained many small sharp bits of stone and husks of flax-seeds4 ,they must also have contained living seeds1 for on the following spring ,mr4 ,carnagie saw grass-plants sprouting out of some of the intersected chambers4 ,i found at ,abinger in ,surrey two burrows terminating in similar chambers at a depth of #cf and #da inches1 and these were lined or paved with little pebbles1 about as large as mustard seeds2 and in one of the chambers there was a decayed oat-grain1 with its husk4 ,hensen likewise states that the bottoms of the burrows are lined with little stones2 and where these could not be procured1 seeds1 apparently of the pear1 had been used1 as many as fifteen having been carried down into a single burrow1 one of which had germinated4 #ajh ,we thus see how easily a botanist might be deceived who wished to learn how long deeply buried seeds remained alive1 if he were to collect earth from a considerable depth1 on the supposition that it could contain only seeds which had long lain buried4 ,it is probable that the little stones1 as well as the seeds1 are carried down from the surface by being swallowed2 for a surprising number of glass beads1 bits of tile and of glass were certainly thus carried down by worms kept in pots2 but some may have been carried down within their mouths4 ,the sole conjecture which ,i can form why worms line their winter-quarters with little stones and seeds1 is to prevent their closely coiled-up bodies from coming into close contact with the surrounding cold soil2 and such contact would perhaps interfere with their respiration which is effected by the skin alone4 ,a worm after swallowing earth1 whether for making its burrow or for food1 soon comes to the surface to empty its body4 ,the ejected earth is thoroughly mingled with the intestinal secretions1 and is thus rendered viscid4 ,after being dried it sets hard4 ,i have watched worms during the act of ejection1 and when the earth was in a very liquid state it was ejected in little spurts1 and by a slow peristaltic movement when not so liquid4 ,it is not cast indifferently on any side1 but with some care1 first on one and then on another side2 the tail being used almost like a trowel4 ,when a worm comes to the surface to eject earth1 the tail protrudes1 but when it collects leaves its head must protrude4 ,worms therefore must have the power of turning round in their closely-fitting burrows2 and this1 as it appears to us1 would be a difficult feat4 ,as soon as a little heap has been formed1 the worm apparently avoids1 for the sake of safety1 protruding its tail2 and the earthy matter is forced up through the previously deposited soft mass4 ,the mouth of the same burrow is used for this purpose for a considerable time4 ,in the case of the tower-like castings 7see ,fig4 #b7 near ,nice1 and of the similar but still taller towers from ,bengal 7hereafter to be described and figured71 a considerable degree of skill is exhibited in their construction4 ,dr4 ,king also observed that the passage up these towers hardly ever ran in the same exact line with the underlying burrow1 so that a thin cylindrical object such as a haulm of grass1 could not be passed down the tower into the burrow2 and this change of direction probably serves in some manner as a protection4 ,worms do not always eject their castings on the surface of the ground4 ,when they can find any cavity1 as when burrowing in newly turned-up earth1 or between the stems of banked-up plants1 they deposit their castings in such places4 ,so again any hollow beneath a large stone lying on the surface of the ground1 is soon filled up with their castings4 ,according to ,hensen1 old burrows are habitually used for this purpose2 but as far as my experience serves1 this is not the case1 excepting with those near the surface in recently dug ground4 ,i think that ,hensen may have been deceived by the walls of old burrows1 lined with black earth1 having sunk in or collapsed2 for black streaks are thus left1 and these are conspicuous when passing through light-coloured soil1 and might be mistaken for completely filled-up burrows4 ,it is certain that old burrows collapse in the course of time2 for as we shall see in the next chapter1 the fine earth voided by worms1 if spread out uniformly1 would form in many places in the course of a year a layer #j4b of an inch in thickness2 so that at any rate this large amount is not deposited within the old unused burrows4 ,if the burrows did not collapse1 the whole ground would be first thickly riddled with holes to a depth of about ten inches1 and in fifty years a hollow unsupported space1 ten inches in depth1 would be left4 ,the holes left by the decay of successively formed roots of trees and plants must likewise collapse in the course of time4 ,the burrows of worms run down perpendicularly or a little obliquely1 and where the soil is at all argillaceous1 there is no difficulty in believing that the walls would slowly flow or slide inwards during very wet weather4 ,when1 however1 the soil is sandy or mingled with many small stones1 it can hardly be viscous enough to flow inwards during even the wettest weather2 but another agency may here come into play4 ,after much rain the ground swells1 and as it cannot expand laterally1 the surface rises2 during dry weather it sinks again4 ,for instance1 a large flat stone laid on the surface of a field sank #c4cc mm4 whilst the weather was dry between ,may #ith and ,june #acth1 and rose #a4ia mm1 between ,september #gth and #aith of the same year1 much rain having fallen during the latter part of this time4 ,during frosts and thaws the movements were twice as great4 ,these observations were made by my son ,horace1 who will hereafter publish an account of the movements of this stone during successive wet and dry seasons1 and of the effects of its being undermined by worms4 ,now when the ground swells1 if it be penetrated by cylindrical holes1 such as worm-burrows1 their walls will tend to yield and be pressed inwards2 and the yielding will be greater in the deeper parts 7supposing the whole to be equally moistened7 from the greater weight of the superincumbent soil which has to be raised1 than in the parts near the surface4 ,when the ground dries1 the walls will shrink a little and the burrows will be a little enlarged4 ,their enlargement1 however1 through the lateral contraction of the ground1 will not be favoured1 but rather opposed1 by the weight of the superincumbent soil4 ,distribution of ,worms4--,earth-worms are found in all parts of the world1 and some of the genera have an enormous range4 #aac ,they inhabit the most isolated islands2 they abound in ,iceland1 and are known to exist in the ,west ,indies1 ,st4 ,helena1 ,madagascar1 ,new ,caledonia and ,tahiti4 ,in the ,antarctic regions1 worms from ,kerguelen ,land have been described by ,ray ,lankester2 and ,i found them in the ,falkland ,islands4 ,how they reach such isolated islands is at present quite unknown4 ,they are easily killed by salt-water1 and it does not appear probable that young worms or their egg-capsules could be carried in earth adhering to the feet or beaks of land-birds4 ,moreover ,kerguelen ,land is not now inhabited by any land-bird4 ,in this volume we are chiefly concerned with the earth cast up by worms1 and ,i have gleaned a few facts on this subject with respect to distant lands4 ,worms throw up plenty of castings in the ,united ,states4 ,in ,venezuela1 castings1 probably ejected by species of ,urochta1 are common in the gardens and fields1 but not in the forests1 as ,i hear from ,dr4 ,ernst of ,caracas4 ,he collected #aef castings from the court-yard of his house1 having an area of #bjj square yards4 ,they varied in bulk from half a cubic centimeter to five cubic centimeters1 and were on an average three cubic centimeters4 ,they were1 therefore1 of small size in comparison with those often found in ,england2 for six large castings from a field near my house averaged #af cubic centimeters4 ,several species of earth-worms are common in ,st4 ,catharina in ,south ,brazil1 and ,fritz ,mller informs me 8that in most parts of the forests and pasture-lands1 the whole soil1 to a depth of a quarter of a metre1 looks as if it had passed repeatedly through the intestines of earth-worms1 even where hardly any castings are to be seen on the surface40 ,a gigantic but very rare species is found there1 the burrows of which are sometimes even two centimeters or nearly #j4h of an inch in diameter1 and which apparently penetrate the ground to a great depth4 ,in the dry climate of ,new ,south ,wales1 ,i hardly expected that worms would be common2 but ,dr4 ,g4 ,krefft of ,sydney1 to whom ,i applied1 after making inquiries from gardeners and others1 and from his own observations1 informs me that their castings abound4 ,he sent me some collected after heavy rain1 and they consisted of little pellets1 about #j4ae inch in diameter2 and the blackened sandy earth of which they were formed still cohered with considerable tenacity4 ,the late ,mr4 ,john ,scott of the ,botanic ,gardens near ,calcutta made many observations for me on worms living under the hot and humid climate of ,bengal4 ,the castings abound almost everywhere1 in jungles and in the open ground1 to a greater degree1 as he thinks1 than in ,england4 ,after the water has subsided from the flooded rice-fields1 the whole surface very soon becomes studded with castings--a fact which much surprised ,mr4 ,scott1 as he did not know how long worms could survive beneath water4 ,they cause much trouble in the ,botanic garden1 8for some of the finest of our lawns can be kept in anything like order only by being almost daily rolled2 if left undisturbed for a few days they become studded with large castings40 ,these closely resemble those described as abounding near ,nice2 and they are probably the work of a species of ,perichta4 ,they stand up like towers1 with an open passage in the centre4 ,picture3 ,fig4 #c3 ,a tower-like casting4 ,fig4 #d3 ,a casting from the ,nilgiri ,mountains ,a figure of one of these castings from a photograph is here given 7,fig4 #c74 ,the largest received by me was #c inches in height and #a4ce inch in diameter2 another was only inch in diameter and #b in height4 ,in the following year1 ,mr4 ,scott measured several of the largest2 one was #f inches in height and nearly #a in diameter3 two others were #e inches in height and respectively #b and rather more than #b inches in diameter4 ,the average weight of the #bb castings sent to me was #ce grammes 7#a oz472 and one of them weighed #dd4h grammes 7or #b oz474 ,all these castings were thrown up either in one night or in two4 ,where the ground in ,bengal is dry1 as under large trees1 castings of a different kind are found in vast numbers3 these consist of little oval or conical bodies1 from about the #a_/bj to rather above #a_/aj of an inch in length4 ,they are obviously voided by a distinct species of worms4 ,the period during which worms near ,calcutta display such extraordinary activity lasts for only a little over two months1 namely1 during the cool season after the rains4 ,at this time they are generally found within about #aj inches beneath the surface4 ,during the hot season they burrow to a greater depth1 and are then found coiled up and apparently hybernating4 ,mr4 ,scott has never seen them at a greater depth than #b feet1 but has heard of their having been found at #d feet4 ,within the forests1 fresh castings may be found even during the hot season4 ,the worms in the ,botanic garden1 during the cool and dry season1 draw many leaves and little sticks into the mouths of their burrows1 like our ,english worms2 but they rarely act in this manner during the rainy season4 ,mr4 ,scott saw worm-castings on the lofty mountains of ,sikkim in ,north ,india4 ,in ,south ,india ,dr4 ,king found in one place1 on the plateau of the ,nilgiris1 at an elevation of #gjjj feet1 8a good many castings10 which are interesting for their great size4 ,the worms which eject them are seen only during the wet season1 and are reported to be from #ab to #ae inches in length1 and as thick as a man's little finger4 ,these castings were collected by ,dr4 ,king after a period of #aaj days without any rain2 and they must have been ejected either during the north-east or more probably during the previous south-west monsoon2 for their surfaces had suffered some disintegration and they were penetrated by many fine roots4 ,a drawing is here given 7,fig4 #d7 of one which seems to have best retained its original size and appearance4 ,notwithstanding some loss from disintegration1 five of the largest of these castings 7after having been well sun-dried7 weighed each on an average #hi4e grammes1 or above #c oz42 and the largest weighed #abc4ad grammes1 or #d oz41--that is1 above a quarter of a pound6 ,the largest convolutions were rather more than one inch in diameter2 but it is probable that they had subsided a little whilst soft1 and that their diameters had thus been increased4 ,some had flowed so much that they now consisted of a pile of almost flat confluent cakes4 ,all were formed of fine1 rather light-coloured earth1 and were surprisingly hard and compact1 owing no doubt to the animal matter by which the particles of earth had been cemented together4 ,they did not disintegrate1 even when left for some hours in water4 ,although they had been cast up on the surface of gravelly soil1 they contained extremely few bits of rock1 the largest of which was only #j4ae inch in diameter4 ,dr4 ,king saw in ,ceylon a worm about #b feet in length and inch in diameter2 and he was told that it was a very common species during the wet season4 ,these worms must throw up castings at least as large as those on the ,nilgiri ,mountains2 but ,dr4 ,king saw none during his short visit to ,ceylon4 ,sufficient facts have now been given1 showing that worms do much work in bringing up fine earth to the surface in most or all parts of the world1 and under the most different climates4 ,,chapter ,,iii4 ,,the ,,amount ,,of ,,fine ,,earth ,,brought ,,up ,,by ,,worms ,,to ,,the ,,surface4 ,rate at which various objects strewed on the surface of grass-fields are covered up by the castings of worms--,the burial of a paved path--,the slow subsidence of great stones left on the surface--,the number of worms which live within a given space--,the weight of earth ejected from a burrow1 and from all the burrows within a given space--,the thickness of the layer of mould which the castings on a given space would form within a given time if uniformly spread out--,the slow rate at which mould can increase to a great thickness--,conclusion4 ,,we now come to the more immediate subject of this volume1 namely1 the amount of earth which is brought up by worms from beneath the surface1 and is afterwards spread out more or less completely by the rain and wind4 ,the amount can be judged of by two methods1--by the rate at which objects left on the surface are buried1 and more accurately by weighing the quantity brought up within a given time4 ,we will begin with the first method1 as it was first followed4 ,near ,mael ,hall in ,staffordshire1 quick-lime had been spread about the year #ahbg thickly over a field of good pasture-land1 which had not since been ploughed4 ,some square holes were dug in this field in the beginning of ,october #ahcg2 and the sections showed a layer of turf1 formed by the matted roots of the grasses1 inch in thickness1 beneath which1 at a depth of #b inches 7or #c inches from the surface71 a layer of the lime in powder or in small lumps could be distinctly seen running all round the vertical sides of the holes4 ,the soil beneath the layer of lime was either gravelly or of a coarse sandy nature1 and differed considerably in appearance from the overlying dark-coloured fine mould4 ,coal-cinders had been spread over a part of this same field either in the year #ahcc or #ahcd2 and when the above holes were dug1 that is after an interval of #c or #d years1 the cinders formed a line of black spots round the holes1 at a depth of #a inch beneath the surface1 parallel to and above the white layer of lime4 ,over another part of this field cinders had been strewed1 only about half-a-year before1 and these either still lay on the surface or were entangled among the roots of the grasses2 and ,i here saw the commencement of the burying process1 for worm-castings had been heaped on several of the smaller fragments4 ,after an interval of #d years this field was re-examined1 and now the two layers of lime and cinders were found almost everywhere at a greater depth than before by nearly #a inch1 we will say by of an inch4 ,therefore mould to an average thickness of #j4bb of an inch had been annually brought up by the worms1 and had been spread over the surface of this field4 ,coal-cinders had been strewed over another field1 at a date which could not be positively ascertained1 so thickly that they formed 7,october1 #ahcg7 a layer1 #a inch in thickness at a depth of about #c inches from the surface4 ,the layer was so continuous that the over-lying dark vegetable mould was connected with the sub-soil of red clay only by the roots of the grasses2 and when these were broken1 the mould and the red clay fell apart4 ,in a third field1 on which coal-cinders and burnt marl had been strewed several times at unknown dates1 holes were dug in #ahdb2 and a layer of cinders could be traced at a depth of #c inches1 beneath which at a depth of #i inches from the surface there was a line of cinders together with burnt marl4 ,on the sides of one hole there were two layers of cinders1 at #b and #c inches beneath the surface2 and below them at a depth in parts of #i1 and in other parts of #aj inches there were fragments of burnt marl4 ,in a fourth field two layers of lime1 one above the other1 could be distinctly traced1 and beneath them a layer of cinders and burnt marl at a depth of from #aj to #ab inches below the surface4 ,picture3 ,fig4 #e3 ,section of the vegetable mould in a field4 ,fig4 #f3 ,traverse section across a large stone ,a piece of waste1 swampy land was enclosed1 drained1 ploughed1 harrowed and thickly covered in the year #ahbb with burnt marl and cinders4 ,it was sowed with grass seeds1 and now supports a tolerably good but coarse pasture4 ,holes were dug in this field in #ahcg1 or #ae years after its reclamation1 and we see in the accompanying diagram 7,fig4 #e71 reduced to half of the natural scale1 that the turf was inch thick1 beneath which there was a layer of vegetable mould #b inches thick4 ,this layer did not contain fragments of any kind2 but beneath it there was a layer of mould1 #a inch in thickness1 full of fragments of burnt marl1 conspicuous from their red colour1 one of which near the bottom was an inch in length2 and other fragments of coal-cinders together with a few white quartz pebbles4 ,beneath this layer and at a depth of #d inches from the surface1 the original black1 peaty1 sandy soil with a few quartz pebbles was encountered4 ,here therefore the fragments of burnt marl and cinders had been covered in the course of #ae years by a layer of fine vegetable mould1 only #b inches in thickness1 excluding the turf4 ,six and a half years subsequently this field was re-examined1 and the fragments were now found at from #d to #e inches beneath the surface4 ,so that in this interval of #f years1 about #a inch of mould had been added to the superficial layer4 ,i am surprised that a greater quantity had not been brought up during the whole #ba years1 for in the closely underlying black1 peaty soil there were many worms4 ,it is1 however1 probable that formerly1 whilst the land remained poor1 worms were scanty2 and the mould would then have accumulated slowly4 ,the average annual increase of thickness for the whole period is #j4ai of an inch4 ,two other cases are worth recording4 ,in the spring of #ahce1 a field1 which had long existed as poor pasture and was so swampy that it trembled slightly when stamped on1 was thickly covered with red sand so that the whole surface appeared at first bright red4 ,when holes were dug in this field after an interval of about #b years1 the sand formed a layer at a depth of in4 beneath the surface4 ,in #ahdb 7i4e41 #g years after the sand had been laid on7 fresh holes were dug1 and now the red sand formed a distinct layer1 #b inches beneath the surface1 or #a inch beneath the turf2 so that on an average1 #j4ba inch of mould had been annually brought to the surface4 ,immediately beneath the layer of red sand1 the original substratum of black sandy peat extended4 ,a grass field1 likewise not far from ,maer ,hall1 had formerly been thickly covered with marl1 and was then left for several years as pasture2 it was afterwards ploughed4 ,a friend had three trenches dug in this field #bh years after the application of the marl1 #abf and a layer of the marl fragments could be traced at a depth1 carefully measured1 of #ab inches in some parts1 and of #ad inches in other parts4 ,this difference in depth depended on the layer being horizontal1 whilst the surface consisted of ridges and furrows from the field having been ploughed4 ,the tenant assured me that it had never been turned up to a greater depth than from #f to #h inches2 and as the fragments formed an unbroken horizontal layer from #ab to #ad inches beneath the surface1 these must have been buried by the worms whilst the land was in pasture before it was ploughed1 for otherwise they would have been indiscriminately scattered by the plough throughout the whole thickness of the soil4 ,four-and-a-half years afterwards ,i had three holes dug in this field1 in which potatoes had been lately planted1 and the layer of marl-fragments was now found #ac inches beneath the bottoms of the furrows1 and therefore probably #ae inches beneath the general level of the field4 ,it should1 however1 be observed that the thickness of the blackish sandy soil1 which had been thrown up by the worms above the marl-fragments in the course of #cb years1 would have measured less than #ae inches1 if the field had always remained as pasture1 for the soil would in this case have been much more compact4 ,the fragments of marl almost rested on an undisturbed substratum of white sand with quartz pebbles2 and as this would be little attractive to worms1 the mould would hereafter be very slowly increased by their action4 ,we will now give some cases of the action of worms1 on land differing widely from the dry sandy or the swampy pastures just described4 ,the chalk formation extends all round my house in ,kent2 and its surface1 from having been exposed during an immense period to the dissolving action of rain-water1 is extremely irregular1 being abruptly festooned and penetrated by many deep well-like cavities4 #abh ,during the dissolution of the chalk1 the insoluble matter1 including a vast number of unrolled flints of all sizes1 has been left on the surface and forms a bed of stiff red clay1 full of flints1 and generally from #f to #ad feet in thickness4 ,over the red clay1 wherever the land has long remained as pasture1 there is a layer a few inches in thickness1 of dark-coloured vegetable mould4 ,a quantity of broken chalk was spread1 on ,december #bj1 #ahdb1 over a part of a field near my house1 which had existed as pasture certainly for #cj1 probably for twice or thrice as many years4 ,the chalk was laid on the land for the sake of observing at some future period to what depth it would become buried4 ,at the end of ,november1 #ahga1 that is after an interval of #bi years1 a trench was dug across this part of the field2 and a line of white nodules could be traced on both sides of the trench1 at a depth of #g inches from the surface4 ,the mould1 therefore1 7excluding the turf7 had here been thrown up at an average rate of #j4bb inch per year4 ,beneath the line of chalk nodules there was in parts hardly any fine earth free of flints1 while in other parts there was a layer1 #b inches in thickness4 ,in this latter case the mould was altogether #i inches thick2 and in one such spot a nodule of chalk and a smooth flint pebble1 both of which must have been left at some former time on the surface1 were found at this depth4 ,at from #aa to #ab inches beneath the surface1 the undisturbed reddish clay1 full of flints1 extended4 ,the appearance of the above nodules of chalk surprised me1 much at first1 as they closely resembled water-worn pebbles1 whereas the freshly-broken fragments had been angular4 ,but on examining the nodules with a lens1 they no longer appeared water-worn1 for their surfaces were pitted through unequal corrosion1 and minute1 sharp points1 formed of broken fossil shells1 projected from them4 ,it was evident that the corners of the original fragments of chalk had been wholly dissolved1 from presenting a large surface to the carbonic acid dissolved in the rain-water and to that generated in soil containing vegetable matter1 as well as to the humus-acids4 #aca ,the projecting corners would also1 relatively to the other parts1 have been embraced by a larger number of living rootlets2 and these have the power of even attacking marble1 as ,sachs has shown4 ,thus1 in the course of #bi years1 buried angular fragments of chalk had been converted into well-rounded nodules4 ,another part of this same field was mossy1 and as it was thought that sifted coal-cinders would improve the pasture1 a thick layer was spread over this part either in #ahdb or #ahdc1 and another layer some years afterwards4 ,in #ahga a trench was here dug1 and many cinders lay in a line at a depth of #g inches beneath the surface1 with another line at a depth of #e inches parallel to the one beneath4 ,in another part of this field1 which had formerly existed as a separate one1 and which it was believed had been pasture-land for more than a century1 trenches were dug to see how thick the vegetable mould was4 ,by chance the first trench was made at a spot where at some former period1 certainly more than forty years before1 a large hole had been filled up with coarse red clay1 flints1 fragments of chalk1 and gravel2 and here the fine vegetable mould was only from #d to #d inches in thickness4 ,in another and undisturbed place1 the mould varied much in thickness1 namely1 from #f to #h inches2 beneath which a few small fragments of brick were found in one place4 ,from these several cases1 it would appear that during the last #bi years mould has been heaped on the surface at an average annual rate of from #j4b to #j4bb of an inch4 ,but in this district when a ploughed field is first laid down in grass1 the mould accumulates at a much slower rate4 ,the rate1 also1 must become very much slower after a bed of mould1 several inches in thickness1 has been formed2 for the worms then live chiefly near the surface1 and burrow down to a greater depth so as to bring up fresh earth from below1 only during the winter when the weather is very cold 7at which time worms were found in this field at a depth of #bf inches7 and during summer1 when the weather is very dry4 ,a field1 which adjoins the one just described1 slopes in one part rather steeply 7viz41 at from #aj to #ae72 this part was last ploughed in #ahda1 was then harrowed and left to become pasture-land4 ,for several years it was clothed with an extremely scant vegetation1 and was so thickly covered with small and large flints 7some of them half as large as a child's head7 that the field was always called by my sons 8the stony field40 ,when they ran down the slope the stones clattered together1 ,i remember doubting whether ,i should live to see these larger flints covered with vegetable mould and turf4 ,but the smaller stones disappeared before many years had elapsed1 as did every one of the larger ones after a time2 so that after thirty years 7#ahga7 a horse could gallop over the compact turf from one end of the field to the other1 and not strike a single stone with his shoes4 ,to anyone who remembered the appearance of the field in #ahdb1 the transformation was wonderful4 ,this was certainly the work of the worms1 for though castings were not frequent for several years1 yet some were thrown up month after month1 and these gradually increased in numbers as the pasture improved4 ,in the year #ahga a trench was dug on the above slope1 and the blades of grass were cut off close to the roots1 so that the thickness of the turf and of the vegetable mould could be measured accurately4 ,the turf was rather less than half an inch1 and the mould1 which did not contain any stones1 #b inches in thickness4 ,beneath this lay coarse clayey earth full of flints1 like that in any of the neighbouring ploughed fields4 ,this coarse earth easily fell apart from the overlying mould when a spit was lifted up4 ,the average rate of accumulation of the mould during the whole thirty years was only 4#jhc inch per year 7i4e41 nearly one inch in twelve years72 but the rate must have been much slower at first1 and afterwards considerably quicker4 ,the transformation in the appearance of this field1 which had been effected beneath my eyes1 was afterwards rendered the more striking1 when ,i examined in ,knole ,park a dense forest of lofty beech-trees1 beneath which nothing grew4 ,here the ground was thickly strewed with large naked stones1 and worm-castings were almost wholly absent4 ,obscure lines and irregularities on the surface indicated that the land had been cultivated some centuries ago4 ,it is probable that a thick wood of young beech-trees sprung up so quickly1 that time enough was not allowed for worms to cover up the stones with their castings1 before the site became unfitted for their existence4 ,anyhow the contrast between the state of the now miscalled 8stony field10 well stocked with worms1 and the present state of the ground beneath the old beech-trees in ,knole ,park1 where worms appeared to be absent1 was striking4 ,a narrow path running across part of my lawn was paved in #ahdc with small flagstones1 set edgeways2 but worms threw up many castings and weeds grew thickly between them4 ,during several years the path was weeded and swept2 but ultimately the weeds and worms prevailed1 and the gardener ceased to sweep1 merely mowing off the weeds1 as often as the lawn was mowed4 ,the path soon became almost covered up1 and after several years no trace of it was left4 ,on removing1 in #ahgg1 the thin overlying layer of turf1 the small flag-stones1 all in their proper places1 were found covered by an inch of fine mould4 ,two recently published accounts of substances strewed on the surface of pasture-land1 having become buried through the action of worms1 may be here noticed4 ,the ,rev4 ,h4 ,c4 ,key had a ditch cut in a field1 over which coal-ashes had been spread1 as it was believed1 eighteen years before2 and on the clean-cut perpendicular sides of the ditch1 at a depth of at least seven inches1 there could be seen1 for a length of #fj yards1 8a distinct1 very even1 narrow line of coal-ashes1 mixed with small coal1 perfectly parallel with the top-sward40 #acf;a ,this parallelism and the length of the section give interest to the case4 ,secondly1 ,mr4 ,dancer states #acf;b that crushed bones had been thickly strewed over a field2 and 8some years afterwards0 these were found 8several inches below the surface1 at a uniform depth40 ,the ,rev4 ,mr4 ,zincke informs me that he has lately had an orchard dug to the unusual depth of #d feet4 ,the upper #ah inches consisted of dark-coloured vegetable mould1 and the next #ah inches of sandy loam1 containing in the lower part many rolled pieces of sandstone1 with some bits of brick and tile1 probably of ,roman origin1 as remains of this period have been found close by4 ,the sandy loam rested on an indurated ferruginous pan of yellow clay1 on the surface of which two perfect celts were found4 ,if1 as seems probable1 the celts were originally left on the surface of the land1 they have since been covered up with earth #c feet in thickness1 all of which has probably passed through the bodies of worms1 excepting the stones which may have been scattered on the surface at different times1 together with manure or by other means4 ,it is difficult otherwise to understand the source of the #ah inches of sandy loam1 which differed from the overlying dark vegetable mould1 after both had been burnt1 only in being of a brighter red colour1 and in not being quite so fine-grained4 ,but on this view we must suppose that the carbon in vegetable mould1 when it lies at some little depth beneath the surface and does not continually receive decaying vegetable matter from above1 loses its dark colour in the course of centuries2 but whether this is probable ,i do not know4 ,worms appear to act in the same manner in ,new ,zealand as in ,europe2 for ,professor ,j4 von ,haast has described #ach;a a section near the coast1 consisting of mica-schist1 8covered by #e or #f feet of loess1 above which about #ab inches of vegetable soil had accumulated40 ,between the loess and the mould there was a layer from #c to #f inches in thickness1 consisting of 8cores1 implements1 flakes1 and chips1 all manufactured from hard basaltic rock40 ,it is therefore probable that the aborigines1 at some former period1 had left these objects on the surface1 and that they had afterwards been slowly covered up by the castings of worms4 ,farmers in ,england are well aware that objects of all kinds1 left on the surface of pasture-land1 after a time disappear1 or1 as they say1 work themselves downwards4 ,how powdered lime1 cinders1 and heavy stones1 can work down1 and at the same rate1 through the matted roots of a grass-covered surface1 is a question which has probably never occurred to them4 #ach;b ,the ,sinking of great ,stones through the ,action of ,worms4--,when a stone of large size and of irregular shape is left on the surface of the ground1 it rests1 of course1 on the more protuberant parts2 but worms soon fill up with their castings all the hollow spaces on the lower side2 for1 as ,hensen remarks1 they like the shelter of stones4 ,as soon as the hollows are filled up1 the worms eject the earth which they have swallowed beyond the circumference of the stones2 and thus the surface of the ground is raised all round the stone4 ,as the burrows excavated directly beneath the stone after a time collapse1 the stone sinks a little4 #aci ,hence it is1 that boulders which at some ancient period have rolled down from a rocky mountain or cliff on to a meadow at its base1 are always somewhat imbedded in the soil2 and1 when removed1 leave an exact impression of their lower surfaces in the underlying fine mould4 ,if1 however1 a boulder is of such huge dimensions1 that the earth beneath is kept dry1 such earth will not be inhabited by worms1 and the boulder will not sink into the ground4 ,a lime-kiln formerly stood in a grass-field near ,leith ,hill ,place in ,surrey1 and was pulled down #ce years before my visit2 all the loose rubbish had been carted away1 excepting three large stones of quartzose sandstone1 which it was thought might hereafter be of some use4 ,an old workman remembered that they had been left on a bare surface of broken bricks and mortar1 close to the foundations of the kiln2 but the whole surrounding surface is now covered with turf and mould4 ,the two largest of these stones had never since been moved2 nor could this easily have been done1 as1 when ,i had them removed1 it was the work of two men with levers4 ,one of these stones1 and not the largest1 was #fd inches long1 #ag inches broad1 and from #i to #aj inches in thickness4 ,its lower surface was somewhat protuberant in the middle2 and this part still rested on broken bricks and mortar1 showing the truth of the old workman's account4 ,beneath the brick rubbish the natural sandy soil1 full of fragments of sandstone was found2 and this could have yielded very little1 if at all1 to the weight of the stone1 as might have been expected if the sub-soil had been clay4 ,the surface of the field1 for a distance of about #i inches round the stone1 gradually sloped up to it1 and close to the stone stood in most places about #d inches above the surrounding ground4 ,the base of the stone was buried from #a to #b inches beneath the general level1 and the upper surface projected about #h inches above this level1 or about #d inches above the sloping border of turf4 ,after the removal of the stone it became evident that one of its pointed ends must at first have stood clear above the ground by some inches1 but its upper surface was now on a level with the surrounding turf4 ,when the stone was removed1 an exact cast of its lower side1 forming a shallow crateriform hollow1 was left1 the inner surface of which consisted of fine black mould1 excepting where the more protuberant parts rested on the brick-rubbish4 ,a transverse section of this stone1 together with its bed1 drawn from measurements made after it had been displaced1 is here given on a scale of inch to a foot 7,fig4 #f74 ,the turf-covered border which sloped up to the stone1 consisted of fine vegetable mould1 in one part #g inches in thickness4 ,this evidently consisted of worm-castings1 several of which had been recently ejected4 ,the whole stone had sunk in the thirty-five years1 as far as ,i could judge1 about #a inch2 and this must have been due to the brick-rubbish beneath the more protuberant parts having been undermined by worms4 ,at this rate the upper surface of the stone1 if it had been left undisturbed1 would have sunk to the general level of the field in #bdg years2 but before this could have occurred1 some earth would have been washed down by heavy rain from the castings on the raised border of turf over the upper surface of the stone4 ,the second stone was larger that the one just described1 viz41 #fg inches in length1 #ci in breadth1 and #ae in thickness4 ,the lower surface was nearly flat1 so that the worms must soon have been compelled to eject their castings beyond its circumference4 ,the stone as a whole had sunk about #b inches into the ground4 ,at this rate it would have required #bfb years for its upper surface to have sunk to the general level of the field4 ,the upwardly sloping1 turf-covered border round the stone was broader than in the last case1 viz41 from #ad to #af inches2 and why this should be so1 ,i could see no reason4 ,in most parts this border was not so high as in the last case1 viz41 from #b to #b inches1 but in one place it was as much as #e4 ,its average height close to the stone was probably about #c inches1 and it thinned out to nothing4 ,if so1 a layer of fine earth1 #ae inches in breadth and #a inch in average thickness1 of sufficient length to surround the whole of the much elongated slab1 must have been brought up by the worms in chief part from beneath the stone in the course of #ce years4 ,this amount would be amply sufficient to account for its having sunk about #b inches into the ground2 more especially if we bear in mind that a good deal of the finest earth would have been washed by heavy rain from the castings ejected on the sloping border down to the level of the field4 ,some fresh castings were seen close to the stone4 ,nevertheless1 on digging a large hole to a depth of #ah inches where the stone had lain1 only two worms and a few burrows were seen1 although the soil was damp and seemed favourable for worms4 ,there were some large colonies of ants beneath the stone1 and possibly since their establishment the worms had decreased in number4 ,the third stone was only about half as large as the others2 and two strong boys could together have rolled it over4 ,i have no doubt that it had been rolled over at a moderately recent time1 for it now lay at some distance from the two other stones at the bottom of a little adjoining slope4 ,it rested also on fine earth1 instead of partly on brick-rubbish4 ,in agreement with this conclusion1 the raised surrounding border of turf was only #a inch high in some parts1 and #b inches in other parts4 ,there were no colonies of ants beneath this stone1 and on digging a hole where it had lain1 several burrows and worms were found4 ,at ,stonehenge1 some of the outer ,druidical stones are now prostrate1 having fallen at a remote but unknown period2 and these have become buried to a moderate depth in the ground4 ,they are surrounded by sloping borders of turf1 on which recent castings were seen4 ,close to one of these fallen stones1 which was #ag ft long1 #f ft4 broad1 and #bh inches thick1 a hole was dug2 and here the vegetable mould was at least #i inches in thickness4 ,at this depth a flint was found1 and a little higher up on one side of the hole a fragment of glass4 ,the base of the stone lay about #i inches beneath the level of the surrounding ground1 and its upper surface #ai inches above the ground4 ,a hole was also dug close to a second huge stone1 which in falling had broken into two pieces2 and this must have happened long ago1 judging from the weathered aspect of the fractured ends4 ,the base was buried to a depth of #aj inches1 as was ascertained by driving an iron skewer horizontally into the ground beneath it4 ,the vegetable mould forming the turf-covered sloping border round the stone1 on which many castings had recently been ejected1 was #aj inches in thickness2 and most of this mould must have been brought up by worms from beneath its base4 ,at a distance of #h yards from the stone1 the mould was only #e inches in thickness 7with a piece of tobacco pipe at a depth of #d inches71 and this rested on broken flint and chalk which could not have easily yielded to the pressure or weight of the stone4 ,a straight rod was fixed horizontally 7by the aid of a spirit-level7 across a third fallen stone1 which was #g feet #i inches long2 and the contour of the projecting parts and of the adjoining ground1 which was not quite level1 was thus ascertained1 as shown in the accompanying diagram 7,fig4 #g7 on a scale of inch to a foot4 ,the turf-covered border sloped up to the stone on one side to a height of #d inches1 and on the opposite side to only #b inches above the general level4 ,a hole was dug on the eastern side1 and the base of the stone was here found to lie at a depth of #d inches beneath the general level of the ground1 and of #h inches beneath the top of the sloping turf-covered border4 99 99 99 99 99 ,sufficient evidence has now been given showing that small objects left on the surface of the land where worms abound soon get buried1 and that large stones sink slowly downwards through the same means4 ,every step of the process could be followed1 from the accidental deposition of a single casting on a small object lying loose on the surface1 to its being entangled amidst the matted roots of the turf1 and lastly to its being embedded in the mould at various depths beneath the surface4 ,when the same field was re-examined after the interval of a few years1 such objects were found at a greater depth than before4 ,the straightness and regularity of the lines formed by the imbedded objects1 and their parallelism with the surface of the land1 are the most striking features of the case2 for this parallelism shows how equably the worms must have worked2 the result being1 however1 partly the effect of the washing down of the fresh castings by rain4 ,the specific gravity of the objects does not affect their rate of sinking1 as could be seen by porous cinders1 burnt marl1 chalk and quartz pebbles1 having all sunk to the same depth within the same time4 ,considering the nature of the substratum1 which at ,leith ,hill ,place was sandy soil including many bits of rock1 and at ,stonehenge1 chalk-rubble with broken flints2 considering1 also1 the presence of the turf-covered sloping border of mould round the great fragments of stone at both these places1 their sinking does not appear to have been sensibly aided by their weight1 though this was considerable4 #adg ,on the number of worms which live within a given space4--,we will now show1 firstly1 what a vast number of worms live unseen by us beneath our feet1 and1 secondly1 the actual weight of the earth which they bring up to the surface within a given space and within a given time4 ,hensen1 who has published so full and interesting an account of the habits of worms1 #adh calculates1 from the number which he found in a measured space1 that there must exist #acc1jjj living worms in a hectare of land1 or #ec1gfg in an acre4 ,this latter number of worms would weigh #cef pounds1 taking ,hensen's standard of the weight of a single worm1 namely1 three grams4 ,it should1 however1 be noted that this calculation is founded on the numbers found in a garden1 and ,hensen believes that worms are here twice as numerous as in corn-fields4 ,the above result1 astonishing though it be1 seems to me credible1 judging from the number of worms which ,i have sometimes seen1 and from the number daily destroyed by birds without the species being exterminated4 ,some barrels of bad ale were left on ,mr4 ,miller's land1 #adi in the hope of making vinegar1 but the vinegar proved bad1 and the barrels were upset4 ,it should be premised that acetic acid is so deadly a poison to worms that ,perrier found that a glass rod dipped into this acid and then into a considerable body of water in which worms were immersed1 invariably killed them quickly4 ,on the morning after the barrels had been upset1 8the heaps of worms which lay dead on the ground were so amazing1 that if ,mr4 ,miller had not seen them1 he could not have thought it possible for such numbers to have existed in the space40 ,as further evidence of the large number of worms which live in the ground1 ,hensen states that he found in a garden sixty-four open burrows in a space of #ad square feet1 that is1 nine in #b square feet4 ,but the burrows are sometimes much more numerous1 for when digging in a grass-field near ,maer ,hall1 ,i found a cake of dry earth1 as large as my two open hands1 which was penetrated by seven burrows1 as large as goose-quills4 ,weight of the earth ejected from a single burrow1 and from all the burrows within a given space4--,with respect to the weight of the earth daily ejected by worms1 ,hensen found that it amounted1 in the case of some worms which he kept in confinement1 and which he appears to have fed with leaves1 to only #j4e gram1 or less than #h grains per diem4 ,but a very much larger amount must be ejected by worms in their natural state1 at the periods when they consume earth as food instead of leaves1 and when they are making deep burrows4 ,this is rendered almost certain by the following weights of the castings thrown up at the mouths of single burrows2 the whole of which appeared to have been ejected within no long time1 as was certainly the case in several instances4 ,the castings were dried 7excepting in one specified instance7 by exposure during many days to the sun or before a hot fire4 ,,weight ,,of ,,the ,,castings ,,accumulated ,,at ,,the ,,mouth ,,of ,a ,,single ,,burrow4 7#a47 ,down1 ,kent 7sub-soil red clay1 full of flints1 #c4ih over-lying the chalk74 ,the largest casting which ,i could find on the flanks of a steep valley1 the sub-soil being here shallow4 ,in this one case1 the casting was not well dried 7#b47 ,down4--,largest casting which ,i could find 7consisting #c4hg chiefly of calcareous matter71 on extremely poor pasture land at the bottom of the valley mentioned under 7#a47 7#c47 ,down4--,a large casting1 but not of unusual size1 from #a4bb a nearly level field1 poor pasture1 laid down in a grass about #ce years before 7#d47 ,down4 ,average weight of #aa not large castings #j4g ejected on a sloping surface on my lawn1 after they had suffered some loss of weight from being exposed during a considerable length of time to rain 7#e47 ,near ,nice in ,france4--,average weight of #ab castings of #a4cg ordinary dimensions1 collected by ,dr4 ,king on land which had not been mown for a long time and where worms abounded1 viz41 a lawn protected by shrubberies near the sea2 soil sandy and calcareous2 these castings had been exposed for some time to rain1 before being collected1 and must have lost some weight by disintegration1 but they still retained their form 7#f47 ,the heaviest of the above twelve castings #a4gf 7#g47 ,lower ,bengal4--,average weight of #bb castings1 #a4bd collected by ,mr4 ,j4 ,scott1 and stated by him to have been thrown up in the course of one or two nights 7#h47 ,the heaviest of the above #bb castings #b4ji 7#i47 ,nilgiri ,mountains1 ,s4 ,india2 average weight of the #e #c4ae largest castings collected by ,dr4 ,king4 ,they had been exposed to the rain of the last monsoon1 and must have lost some weight 7#aj47 ,the heaviest of the above #e castings #d4cd ,in this table we see that castings which had been ejected at the mouth of the same burrow1 and which in most cases appeared fresh and always retained their vermiform configuration1 generally exceeded an ounce in weight after being dried1 and sometimes nearly equalled a quarter of a pound4 ,on the ,nilgiri mountains one casting even exceeded this latter weight4 ,the largest castings in ,england were found on extremely poor pasture-land2 and these1 as far as ,i have seen1 are generally larger than those on land producing a rich vegetation4 ,it would appear that worms have to swallow a greater amount of earth on poor than on rich land1 in order to obtain sufficient nutriment4 ,with respect to the tower-like castings near ,nice 7,nos4 #e and #f in the above table71 ,dr4 ,king often found five or six of them on a square foot of surface2 and these1 judging from their average weight1 would have weighed together #g ounces2 so that the weight of those on a square yard would have been #d lb4 #c oz4 ,dr4 ,king collected1 near the close of the year #ahgb1 all the castings which still retained their vermiform shape1 whether broken down or not1 from a square foot1 in a place abounding with worms1 on the summit of a bank1 where no castings could have rolled down from above4 ,these castings must have been ejected1 as he judged from their appearance in reference to the rainy and dry periods near ,nice1 within the previous five or six months2 they weighed #i oz41 or #e lb4 #e oz4 per square yard4 ,after an interval of four months1 ,dr4 ,king collected all the castings subsequently ejected on the same square foot of surface1 and they weighed #b oz41 or #a lb4 #f oz4 per square yard4 ,therefore within about ten months1 or we will say for safety's sake within a year1 #ab oz4 of castings were thrown up on this one square foot1 or #f4ge pounds on the square yard2 and this would give #ad4eh tons per acre4 ,in a field at the bottom of a valley in the chalk 7see ,no4 #b in the foregoing table71 a square yard was measured at a spot where very large castings abounded2 they appeared1 however1 almost equally numerous in a few other places4 ,these castings1 which retained perfectly their vermiform shape1 were collected2 and they weighed when partially dried1 #a lb4 #ac oz4 ,this field had been rolled with a heavy agricultural roller fifty-two days before1 and this would certainly have flattened every single casting on the land4 ,the weather had been very dry for two or three weeks before the day of collection1 so that not one casting appeared fresh or had been recently ejected4 ,we may therefore assume that those which were weighed had been ejected within1 we will say1 forty days from the time when the field was rolled1--that is1 twelve days short of the whole intervening period4 ,i had examined the same part of the field shortly before it was rolled1 and it then abounded with fresh castings4 ,worms do not work in dry weather during the summer1 or in winter during severe frosts4 ,if we assume that they work for only half the year--though this is too low an estimate--then the worms in this field would eject during the year1 #h4chg pounds per square yard2 or #ah4ab tons per acre1 assuming the whole surface to be equally productive in castings4 ,in the foregoing cases some of the necessary data had to be estimated1 but in the two following cases the results are much more trustworthy4 ,a lady1 on whose accuracy ,i can implicitly rely1 offered to collect during a year all the castings thrown up on two separate square yards1 near ,leith ,hill ,place1 in ,surrey4 ,the amount collected was1 however1 somewhat less than that originally ejected by the worms2 for1 as ,i have repeatedly observed1 a good deal of the finest earth is washed away1 whenever castings are thrown up during or shortly before heavy rain4 ,small portions also adhered to the surrounding blades of grass1 and it required too much time to detach every one of them4 ,on sandy soil1 as in the present instance1 castings are liable to crumble after dry weather1 and particles were thus often lost4 ,the lady also occasionally left home for a week or two1 and at such times the castings must have suffered still greater loss from exposure to the weather4 ,these losses were1 however1 compensated to some extent by the collections having been made on one of the squares for four days1 and on the other square for two days more than the year4 ,a space was selected 7,october #ith1 #ahgj7 for one of the squares on a broad1 grass-covered terrace1 which had been mowed and swept during many years4 ,it faced the south1 but was shaded during part of the day by trees4 ,it had been formed at least a century ago by a great accumulation of small and large fragments of sandstone1 together with some sandy earth1 rammed down level4 ,it is probable that it was at first protected by being covered with turf4 ,this terrace1 judging from the number of castings on it1 was rather unfavourable for the existence of worms1 in comparison with the neighbouring fields and an upper terrace4 ,it was indeed surprising that as many worms could live here as were seen2 for on digging a hole in this terrace1 the black vegetable mould together with the turf was only four inches in thickness1 beneath which lay the level surface of light-coloured sandy soil1 with many fragments of sandstone4 ,before any castings were collected all the previously existing ones were carefully removed4 ,the last day's collection was on ,october #adth1 #ahga4 ,the castings were then well dried before a fire2 and they weighed exactly #c lbs4 ,this would give for an acre of similar land #g4ef tons of dry earth annually ejected by worms4 ,the second square was marked on unenclosed common land1 at a height of about #gjj ft4 above the sea1 at some little distance from ,leith ,hill ,tower4 ,the surface was clothed with short1 fine turf1 and had never been disturbed by the hand of man4 ,the spot selected appeared neither particularly favourable nor the reverse for worms2 but ,i have often noticed that castings are especially abundant on common land1 and this may1 perhaps1 be attributed to the poorness of the soil4 ,the vegetable mould was here between three and four inches in thickness4 ,as this spot was at some distance from the house where the lady lived1 the castings were not collected at such short intervals of time as those on the terrace2 consequently the loss of fine earth during rainy weather must have been greater in this than in the last case4 ,the castings moreover were more sandy1 and in collecting them during dry weather they sometimes crumbled into dust1 and much was thus lost4 ,therefore it is certain that the worms brought up to the surface considerably more earth than that which was collected4 ,the last collection was made on ,october #bgth1 #ahga2 i4e41 #cfg days after the square had been marked out and the surface cleared of all pre-existing castings4 ,the collected castings1 after being well dried1 weighed #g4dec pounds2 and this would give1 for an acre of the same kind of land1 #af4a tons of annually ejected dry earth4 ,,summary ,,of ,,the ,,four ,,foregoing ,,cases4 7#a47 ,castings ejected near ,nice within about a year1 collected by ,dr4 ,king on a square foot of surface1 calculated to yield per acre #ad4eh tons4 7#b47 ,castings ejected during about #dj days on a square yard1 in a field of poor pasture at the bottom of a large valley in the ,chalk1 calculated to yield annually per acre #ah4ab tons4 7#c47 ,castings collected from a square yard on an old terrace at ,leith ,hill ,place1 during #cfi days1 calculated to yield annually per acre #g4ef tons4 7#d47 ,castings collected from a square yard on ,leith ,hill ,common during #cfg days1 calculated to yield annually per acre #af4a tons4 ,the thickness of the layer of mould1 which castings ejected during a year would form if uniformly spread out4--,as we know1 from the two last cases in the above summary1 the weight of the dried castings ejected by worms during a year on a square yard of surface1 ,i wished to learn how thick a layer of ordinary mould this amount would form if spread uniformly over a square yard4 ,the dry castings were therefore broken into small particles1 and whilst being placed in a measure were well shaken and pressed down4 ,those collected on the ,terrace amounted to #abd4gg cubic inches2 and this amount1 if spread out over a square yard1 would make a layer #j4ifbg inch in thickness4 ,those collected on the ,common amounted to #aig4ef cubic inches1 and would make a similar layer #j4aebd inch in thickness4 ,these thicknesses must1 however1 be corrected1 for the triturated castings1 after being well shaken down and pressed1 did not make nearly so compact a mass as vegetable mould1 though each separate particle was very compact4 ,yet mould is far from being compact1 as is shown by the number of air-bubbles which rise up when the surface is flooded with water4 ,it is moreover penetrated by many fine roots4 ,to ascertain approximately by how much ordinary vegetable mould would be increased in bulk by being broken up into small particles and then dried1 a thin oblong block of somewhat argillaceous mould 7with the turf pared off7 was measured before being broken up1 was well dried and again measured4 ,the drying caused it to shrink by #a_/g of its original bulk1 judging from exterior measurements alone4 ,it was then triturated and partly reduced to powder1 in the same manner as the castings had been treated1 and its bulk now exceeded 7notwithstanding shrinkage from drying7 by #a_/af that of the original block of damp mould4 ,therefore the above calculated thickness of the layer1 formed by the castings from the ,terrace1 after being damped and spread over a square yard1 would have to be reduced by #a_/af2 and this will reduce the layer to #j4ji of an inch1 so that a layer #j4i inch in thickness would be formed in the course of ten years4 ,on the same principle the castings from the ,common would make in the course of a single year a layer #j4adbi inch1 or in the course of #aj years #a4dbi inch1 in thickness4 ,we may say in round numbers that the thickness in the former case would amount to nearly #a inch1 and in the second case to nearly #a inch in #aj years4 ,in order to compare these results with those deduced from the rates at which small objects left on the surfaces of grass-fields become buried 7as described in the early part of this chapter71 we will give the following summary3-- ,,summary ,,of ,,the ,,thickness ,,of ,,the ,,mould ,,accumulated ,,over ,,objects ,,left ,,strewed ,,on ,,the ,,surface1 ,,in ,,the ,,course ,,of ,,ten ,,years4 ,the accumulation of mould during #ad years on the surface of a dry1 sandy1 grass-field near ,maer ,hall1 amounted to #b4b inches in #aj years4 ,the accumulation during #ba years on a swampy field near ,maer ,hall1 amounted to nearly #a4i inch in #aj years4 ,the accumulation during #g years on a very swampy field near ,maer ,hall amounted to #b4a inches in #aj years4 ,the accumulation during #bi years1 on good1 argillaceous pasture-land over the ,chalk at ,down1 amounted to #b4b inches in #aj years4 ,the accumulation during #cj years on the side of a valley over the ,chalk at ,down1 the soil being argillaceous1 very poor1 and only just converted into pasture 7so that it was for some years unfavourable for worms71 amounted to #j4hc inch in #aj years4 ,in these cases 7excepting the last7 it may be seen that the amount of earth brought to the surface during #aj years is somewhat greater than that calculated from the castings which were actually weighed4 ,this excess may be partly accounted for by the loss which the weighed castings had previously undergone through being washed by rain1 by the adhesion of particles to the blades of the surrounding grass1 and by their crumbling when dry4 ,nor must we overlook other agencies which in all ordinary cases add to the amount of mould1 and which would not be included in the castings that were collected1 namely1 the fine earth brought up to the surface by burrowing larv and insects1 especially by ants4 ,the earth brought up by moles generally has a somewhat different appearance from vegetable mould2 but after a time would not be distinguishable from it4 ,in dry countries1 moreover1 the wind plays an important part in carrying dust from one place to another1 and even in ,england it must add to the mould on fields near great roads4 ,but in our country these latter several agencies appear to be of quite subordinate importance in comparison with the action of worms4 ,we have no means of judging how great a weight of earth a single full-sized worm ejects during a year4 ,hensen estimates that #ec1gfg worms exist in an acre of land2 but this is founded on the number found in gardens1 and he believes that only about half as many live in corn-fields4 ,how many live in old pasture land is unknown2 but if we assume that half the above number1 or #bf1hhf worms live on such land1 then taking from the previous summary #ae tons as the weight of the castings annually thrown up on an acre of land1 each worm must annually eject #bj ounces4 ,a full-sized casting at the mouth of a single burrow often exceeds1 as we have seen1 an ounce in weight2 and it is probable that worms eject more than #bj full-sized castings during a year4 ,if they eject annually more than #bj ounces1 we may infer that the worms which live in an acre of pasture land must be less than #bf1hhf in number4 ,worms live chiefly in the superficial mould1 which is usually from #d or #e to #aj and even #ab inches in thickness2 and it is this mould which passes over and over again through their bodies and is brought to the surface4 ,but worms occasionally burrow into the subsoil to a much greater depth1 and on such occasions they bring up earth from this greater depth2 and this process has gone on for countless ages4 ,therefore the superficial layer of mould would ultimately attain1 though at a slower and slower rate1 a thickness equal to the depth to which worms ever burrow1 were there not other opposing agencies at work which carry away to a lower level some of the finest earth which is continually being brought to the surface by worms4 ,how great a thickness vegetable mould ever attains1 ,i have not had good opportunities for observing2 but in the next chapter1 when we consider the burial of ancient buildings1 some facts will be given on this head4 ,in the two last chapters we shall see that the soil is actually increased1 though only to a small degree1 through the agency of worms2 but their chief work is to sift the finer from the coarser particles1 to mingle the whole with vegetable dbris1 and to saturate it with their intestinal secretions4 ,finally1 no one who considers the facts given in this chapter--on the burying of small objects and on the sinking of great stones left on the surface--on the vast number of worms which live within a moderate extent of ground on the weight of the castings ejected from the mouth of the same burrow--on the weight of all the castings ejected within a known time on a measured space--will hereafter1 as ,i believe1 doubt that worms play an important part in nature4 ,,chapter ,,iv4 ,,the ,,part ,,which ,,worms ,,have ,,played ,,in ,,the ,,burial ,,of ,,ancient ,,buildings4 ,the accumulation of rubbish on the sites of great cities independent of the action of worms--,the burial of a ,roman villa at ,abinger--,the floors and walls penetrated by worms--,subsidence of a modern pavement--,the buried pavement at ,beaulieu ,abbey--,roman villas at ,chedworth and ,brading--,the remains of the ,roman town at ,silchester--,the nature of the dbris by which the remains are covered--,the penetration of the tesselated floors and walls by worms--,subsidence of the floors--,thickness of the mould--,the old ,roman city of ,wroxeter--,thickness of the mould--,depth of the foundations of some of the ,buildings--,conclusion4 ,,arch,,ologists are probably not aware how much they owe to worms for the preservation of many ancient objects4 ,coins1 gold ornaments1 stone implements1 c41 if dropped on the surface of the ground1 will infallibly be buried by the castings of worms in a few years1 and will thus be safely preserved1 until the land at some future time is turned up4 ,for instance1 many years ago a grass-field was ploughed on the northern side of the ,severn1 not far from ,shrewsbury2 and a surprising number of iron arrow-heads were found at the bottom of the furrows1 which1 as ,mr4 ,blakeway1 a local antiquary1 believed1 were relics of the battle of ,shrewsbury in the year #adjc1 and no doubt had been originally left strewed on the battle-field4 ,in the present chapter ,i shall show that not only implements1 c41 are thus preserved1 but that the floors and the remains of many ancient buildings in ,england have been buried so effectually1 in large part through the action of worms1 that they have been discovered in recent times solely through various accidents4 ,the enormous beds of rubbish1 several yards in thickness1 which underlie many cities1 such as ,rome1 ,paris1 and ,london1 the lower ones being of great antiquity1 are not here referred to1 as they have not been in any way acted on by worms4 ,when we consider how much matter is daily brought into a great city for building1 fuel1 clothing and food1 and that in old times when the roads were bad and the work of the scavenger was neglected1 a comparatively small amount was carried away1 we may agree with lie de ,beaumont1 who1 in discussing this subject1 says1 8pour une voiture de matriaux qui en sort1 on y en fait entrer cent40 #aff;a ,nor should we overlook the effects of fires1 the demolition of old buildings1 and the removal of rubbish to the nearest vacant space4 ,abinger1 ,surrey4--,late in the autumn of #ahgf1 the ground in an old farm-yard at this place was dug to a depth of #b to #b feet1 and the workmen found various ancient remains4 ,this led ,mr4 ,t4 ,h4 ,farrer of ,abinger ,hall to have an adjoining ploughed field searched4 ,on a trench being dug1 a layer of concrete1 still partly covered with tesser 7small red tiles71 and surrounded on two sides by broken-down walls1 was soon discovered4 ,it is believed1 #aff;b that this room formed part of the atrium or reception-room of a ,roman villa4 ,the walls of two or three other small rooms were afterwards discovered4 ,many fragments of pottery1 other objects1 and coins of several ,roman emperors1 dating from #acc to #cfa1 and perhaps to #cge ,a4,d41 were likewise found4 ,also a half-penny of ,george ,i41 #agae4 ,the presence of this latter coin seems an anomaly2 but no doubt it was dropped on the ground during the last century1 and since then there has been ample time for its burial under a considerable depth of the castings of worms4 ,from the different dates of the ,roman coins we may infer that the building was long inhabited4 ,it was probably ruined and deserted #adjj or #aejj years ago4 ,i was present during the commencement of the excavations 7,august #bj1 #ahgg7 and ,mr4 ,farrer had two deep trenches dug at opposite ends of the atrium1 so that ,i might examine the nature of the soil near the remains4 ,the field sloped from east to west at an angle of about #g2 and one of the two trenches1 shown in the accompanying section 7,fig4 #h7 was at the upper or eastern end4 ,the diagram is on a scale of #a_/bj of an inch to an inch2 but the trench1 which was between #d and #e feet broad1 and in parts above #e feet deep1 has necessarily been reduced out of all proportion4 ,the fine mould over the floor of the atrium varied in thickness from #aa to #af inches2 and on the side of the trench in the section was a little over #ac inches4 ,after the mould had been removed1 the floor appeared as a whole moderately level2 but it sloped in parts at an angle of #a1 and in one place near the outside at as much as #h #cj4 ,the wall surrounding the pavement was built of rough stones1 and was #bc inches in thickness where the trench was dug4 ,its broken summit was here #ac inches1 but in another part #ae inches1 beneath the surface of the field1 being covered by this thickness of mould4 ,in one spot1 however1 it rose to within #f inches of the surface4 ,on two sides of the room1 where the junction of the concrete floor with the bounding walls could be carefully examined1 there was no crack or separation4 ,this trench afterwards proved to have been dug within an adjoining room 7#aa ft4 by #aa ft4 #f in4 in size71 the existence of which was not even suspected whilst ,i was present4 ,picture3 ,fig4 #h3 ,section through the foundations of a buried ,roman villa ,on the side of the trench farthest from the buried wall 7,w71 the mould varied from #i to #ad inches in thickness2 it rested on a mass 7,b7 #bc inches thick of blackish earth1 including many large stones4 ,beneath this was a thin bed of very black mould 7,c71 then a layer of earth full of fragments of mortar 7,d71 and then another thin bed 7about #c inches thick7 7,e7 of very black mould1 which rested on the undisturbed subsoil 7,f7 of firm1 yellowish1 argillaceous sand4 ,the #bc-;inch bed 7,b7 was probably made ground1 as this would have brought up the floor of the room to a level with that of the atrium4 ,the two thin beds of black mould at the bottom of the trench evidently marked two former land-surfaces4 ,outside the walls of the northern room1 many bones1 ashes1 oyster-shells1 broken pottery and an entire pot were subsequently found at a depth of #af inches beneath the surface4 ,the second trench was dug on the western or lower side of the villa3 the mould was here only #f inches in thickness1 and it rested on a mass of fine earth full of stones1 broken tiles and fragments of mortar1 #cd inches in thickness1 beneath which was the undisturbed sand4 ,most of this earth had probably been washed down from the upper part of the field1 and the fragments of stones1 tiles1 c41 must have come from the immediately adjoining ruins4 ,it appears at first sight a surprising fact that this field of light sandy soil should have been cultivated and ploughed during many years1 and that not a vestige of these buildings should have been discovered4 ,no one even suspected that the remains of a ,roman villa lay hidden close beneath the surface4 ,but the fact is less surprising when it is known that the field1 as the bailiff believed1 had never been ploughed to a greater depth than #d inches4 ,it is certain that when the land was first ploughed1 the pavement and the surrounding broken walls must have been covered by at least #d inches of soil1 for otherwise the rotten concrete floor would have been scored by the ploughshare1 the tesser torn up1 and the tops of the old walls knocked down4 ,when the concrete and tesser were first cleared over a space of #ad by #i ft41 the floor which was coated with trodden-down earth exhibited no signs of having been penetrated by worms2 and although the overlying fine mould closely resembled that which in many places has certainly been accumulated by worms1 yet it seemed hardly possible that this mould could have been brought up by worms from beneath the apparently sound floor4 ,it seemed also extremely improbable that the thick walls1 surrounding the room and still united to the concrete1 had been undermined by worms1 and had thus been caused to sink1 being afterwards covered up by their castings4 ,i therefore at first concluded that all the fine mould above the ruins had been washed down from the upper parts of the field2 but we shall soon see that this conclusion was certainly erroneous1 though much fine earth is known to be washed down from the upper part of the field in its present ploughed state during heavy rains4 ,although the concrete floor did not at first appear to have been anywhere penetrated by worms1 yet by the next morning little cakes of the trodden-down earth had been lifted up by worms over the mouths of seven burrows1 which passed through the softer parts of the naked concrete1 or between the interstices of the tesser4 ,on the third morning twenty-five burrows were counted2 and by suddenly lifting up the little cakes of earth1 four worms were seen in the act of quickly retreating4 ,two castings were thrown up during the third night on the floor1 and these were of large size4 ,the season was not favourable for the full activity of worms1 and the weather had lately been hot and dry1 so that most of the worms now lived at a considerable depth4 ,in digging the two trenches many open burrows and some worms were encountered at between #cj and #dj inches beneath the surface2 but at a greater depth they became rare4 ,one worm1 however1 was cut through at #dh1 and another at #ea inches beneath the surface4 ,a fresh humus-lined burrow was also met with at a depth of #eg and another at #fe inches4 ,at greater depths than this1 neither burrows nor worms were seen4 ,as ,i wished to learn how many worms lived beneath the floor of the atrium--a space of about #ad by #i feet--,mr4 ,farrer was so kind as to make observations for me1 during the next seven weeks1 by which time the worms in the surrounding country were in full activity1 and were working near the surface4 ,it is very improbable that worms should have migrated from the adjoining field into the small space of the atrium1 after the superficial mould in which they prefer to live1 had been removed4 ,we may therefore conclude that the burrows and the castings which were seen here during the ensuing seven weeks were the work of the former inhabitants of the space4 ,i will now give a few extracts from ,mr4 ,farrer's notes4 ,aug4 #bfth1 #ahgg2 that is1 five days after the floor had been cleared4 ,on the previous night there had been some heavy rain1 which washed the surface clean1 and now the mouths of forty burrows were counted4 ,parts of the concrete were seen to be solid1 and had never been penetrated by worms1 and here the rain-water lodged4 ,sept4 #eth4--,tracks of worms1 made during the previous night1 could be seen on the surface of the floor1 and five or six vermiform castings had been thrown up4 ,these were defaced4 ,sept4 #abth4--,during the last six days1 the worms have not been active1 though many castings have been ejected in the neighbouring fields2 but on this day the earth was a little raised over the mouths of the burrows1 or castings were ejected1 at ten fresh points4 ,these were defaced4 ,it should be understood that when a fresh burrow is spoken of1 this generally means only that an old burrow has been re-opened4 ,mr4 ,farrer was repeatedly struck with the pertinacity with which the worms re-opened their old burrows1 even when no earth was ejected from them4 ,i have often observed the same fact1 and generally the mouths of the burrows are protected by an accumulation of pebbles1 sticks or leaves4 ,mr4 ,farrer likewise observed that the worms living beneath the floor of the atrium often collected coarse grains of sand1 and such little stones as they could find1 round the mouths of their burrows4 ,sept4 #acth2 soft wet weather4 ,the mouths of the burrows were re-opened1 or castings were ejected1 at #ca points2 these were all defaced4 ,sept4 #adth2 #cd fresh holes or castings2 all defaced4 ,sept4 #aeth2 #dd fresh holes1 only #e castings2 all defaced4 ,sept4 #ahth2 #dc fresh holes1 #h castings2 all defaced4 ,the number of castings on the surrounding fields was now very large4 ,sept4 #aith2 #dj holes1 #h castings2 all defaced4 ,sept4 #bbnd2 #dc holes1 only a few fresh castings2 all defaced4 ,sept4 #bcrd2 #dd holes1 #h castings4 ,sept4 #beth2 #ej holes1 no record of the number of castings4 ,oct4 #acth2 #fa holes1 no record of the number of castings4 ,after an interval of three years1 ,mr4 ,farrer1 at my request1 again looked at the concrete floor1 and found the worms still at work4 ,knowing what great muscular power worms possess1 and seeing how soft the concrete was in many parts1 ,i was not surprised at its having been penetrated by their burrows2 but it is a more surprising fact that the mortar between the rough stones of the thick walls1 surrounding the rooms1 was found by ,mr4 ,farrer to have been penetrated by worms4 ,on ,august #bfth1 that is1 five days after the ruins had been exposed1 he observed four open burrows on the broken summit of the eastern wall 7,w in ,fig4 #h72 and1 on ,september #aeth1 other burrows similarly situated were seen4 ,it should also be noted that in the perpendicular side of the trench 7which was much deeper than is represented in ,fig4 #h7 three recent burrows were seen1 which ran obliquely far down beneath the base of the old wall4 ,we thus see that many worms lived beneath the floor and the walls of the atrium at the time when the excavations were made2 and that they afterwards almost daily brought up earth to the surface from a considerable depth4 ,there is not the slightest reason to doubt that worms have acted in this manner ever since the period when the concrete was sufficiently decayed to allow them to penetrate it2 and even before that period they would have lived beneath the floor1 as soon as it became pervious to rain1 so that the soil beneath was kept damp4 ,the floor and the walls must therefore have been continually undermined2 and fine earth must have been heaped on them during many centuries1 perhaps for a thousand years4 ,if the burrows beneath the floor and walls1 which it is probable were formerly as numerous as they now are1 had not collapsed in the course of time in the manner formerly explained1 the underlying earth would have been riddled with passages like a sponge2 and as this was not the case1 we may feel sure that they have collapsed4 ,the inevitable result of such collapsing during successive centuries1 will have been the slow subsidence of the floor and of the walls1 and their burial beneath the accumulated worm-castings4 ,the subsidence of a floor1 whilst it still remains nearly horizontal1 may at first appear improbable2 but the case presents no more real difficulty than that of loose objects strewed on the surface of a field1 which1 as we have seen1 become buried several inches beneath the surface in the course of a few years1 though still forming a horizontal layer parallel to the surface4 ,the burial of the paved and level path on my lawn1 which took place under my own observation1 is an analogous case4 ,even those parts of the concrete floor which the worms could not penetrate would almost certainly have been undermined1 and would have sunk1 like the great stones at ,leith ,hill ,place and ,stonehenge1 for the soil would have been damp beneath them4 ,but the rate of sinking of the different parts would not have been quite equal1 and the floor was not quite level4 ,the foundations of the boundary walls lie1 as shown in the section1 at a very small depth beneath the surface2 they would therefore have tended to subside at nearly the same rate as the floor4 ,but this would not have occurred if the foundations had been deep1 as in the case of some other ,roman ruins presently to be described4 ,finally1 we may infer that a large part of the fine vegetable mould1 which covered the floor and the broken-down walls of this villa1 in some places to a thickness of #af inches1 was brought up from below by worms4 ,from facts hereafter to be given there can be no doubt that some of the finest earth thus brought up will have been washed down the sloping surface of the field during every heavy shower of rain4 ,if this had not occurred a greater amount of mould would have accumulated over the ruins than that now present4 ,but beside the castings of worms and some earth brought up by insects1 and some accumulation of dust1 much fine earth will have been washed over the ruins from the upper parts of the field1 since it has been under cultivation2 and from over the ruins to the lower parts of the slope2 the present thickness of the mould being the resultant of these several agencies4 99 99 99 99 99 ,i may here append a modern instance of the sinking of a pavement1 communicated to me in #ahga by ,mr4 ,ramsay1 ,director of the ,geological ,survey of ,england4 ,a passage without a roof1 #g feet in length by #c feet #b inches in width1 led from his house into the garden1 and was paved with slabs of ,portland stone4 ,several of these slabs were #af inches square1 others larger1 and some a little smaller4 ,this pavement had subsided about #c inches along the middle of the passage1 and two inches on each side1 as could be seen by the lines of cement by which the slabs had been originally joined to the walls4 ,the pavement had thus become slightly concave along the middle2 but there was no subsidence at the end close to the house4 ,mr4 ,ramsay could not account for this sinking1 until he observed that castings of black mould were frequently ejected along the lines of junction between the slabs2 and these castings were regularly swept away4 ,the several lines of junction1 including those with the lateral walls1 were altogether #ci feet #b inches in length4 ,the pavement did not present the appearance of ever having been renewed1 and the house was believed to have been built about eighty-seven years ago4 ,considering all these circumstances1 ,mr4 ,ramsay does not doubt that the earth brought up by the worms since the pavement was first laid down1 or rather since the decay of the mortar allowed the worms to burrow through it1 and therefore within a much shorter time than the eighty-seven years1 has sufficed to cause the sinking of the pavement to the above amount1 except close to the house1 where the ground beneath would have been kept nearly dry4 ,beaulieu ,abbey1 ,hampshire4--,this abbey was destroyed by ,henry ,,viii41 and there now remains only a portion of the southern aisle-wall4 ,it is believed that the king had most of the stones carried away for building a castle2 and it is certain that they have been removed4 ,the positions of the nave and transepts were ascertained not long ago by the foundations having been found2 and the place is now marked by stones let into the ground4 ,where the abbey formerly stood1 there now extends a smooth grass-covered surface1 which resembles in all respects the rest of the field4 ,the guardian1 a very old man1 said the surface had never been levelled in his time4 ,in the year #ahec1 the ,duke of ,buccleuch had three holes dug in the turf within a few yards of one another1 at the western end of the nave2 and the old tesselated pavement of the abbey was thus discovered4 ,these holes were afterwards surrounded by brickwork1 and protected by trap-doors1 so that the pavement might be readily inspected and preserved4 ,when my son ,william examined the place on ,january #e1 #ahgb1 he found that the pavement in the three holes lay at depths of #f1 #aj and #aa inches beneath the surrounding turf-covered surface4 ,the old guardian asserted that he was often forced to remove worm-castings from the pavement2 and that he had done so about six months before4 ,my son collected all from one of the holes1 the area of which was #e4cb square feet1 and they weighed #g4ig ounces4 ,assuming that this amount had accumulated in six months1 the accumulation during a year on a square yard would be #a4fh pounds1 which1 though a large amount1 is very small compared with what1 as we have seen1 is often ejected on fields and commons4 ,when ,i visited the abbey on ,june #bb1 #ahgg1 the old man said that he had cleared out the holes about a month before1 but a good many castings had since been ejected4 ,i suspect that he imagined that he swept the pavements oftener than he really did1 for the conditions were in several respects very unfavourable for the accumulation of even a moderate amount of castings4 ,the tiles are rather large1 viz41 about #e inches square1 and the mortar between them was in most places sound1 so that the worms were able to bring up earth from below only at certain points4 ,the tiles rested on a bed of concrete1 and the castings in consequence consisted in large part 7viz41 in the proportion of #ai to #cc7 of particles of mortar1 grains of sand1 little fragments of rock1 bricks or tile2 and such substances could hardly be agreeable1 and certainly not nutritious1 to worms4 ,my son dug holes in several places within the former walls of the abbey1 at a distance of several yards from the above described bricked squares4 ,he did not find any tiles1 though these are known to occur in some other parts1 but he came in one spot to concrete on which tiles had once rested4 ,the fine mould beneath the turf on the sides of the several holes1 varied in thickness from only #b to #b inches1 and this rested on a layer from #h to above #aa inches in thickness1 consisting of fragments of mortar and stone-rubbish with the interstices compactly filled up with black mould4 ,in the surrounding field1 at a distance of #bj yards from the abbey1 the fine vegetable mould was #aa inches thick4 ,we may conclude from these facts that when the abbey was destroyed and the stones removed1 a layer of rubbish was left over the whole surface1 and that as soon as the worms were able to penetrate the decayed concrete and the joints between the tiles1 they slowly filled up the interstices in the overlying rubbish with their castings1 which were afterwards accumulated to a thickness of nearly three inches over the whole surface4 ,if we add to this latter amount the mould between the fragments of stones1 some five or six inches of mould must have been brought up from beneath the concrete or tiles4 ,the concrete or tiles will consequently have subsided to nearly this amount4 ,the bases of the columns of the aisles are now buried beneath mould and turf4 ,it is not probable that they can have been undermined by worms1 for their foundations would no doubt have been laid at a considerable depth4 ,if they have not subsided1 the stones of which the columns were constructed must have been removed from beneath the former level of the floor4 ,chedworth1 ,gloucestershire4--,the remains of a large ,roman villa were discovered here in #ahff1 on ground which had been covered with wood from time immemorial4 ,no suspicion seems ever to have been entertained that ancient buildings lay buried here1 until a gamekeeper1 in digging for rabbits1 encountered some remains4 #ahc ,but subsequently the tops of some stone walls were detected in parts of the wood1 projecting a little above the surface of the ground4 ,most of the coins found here belonged to ,constans 7who died #cej ,a4,d47 and the ,constantine family4 ,my sons ,francis and ,horace visited the place in ,november #ahgg1 for the sake of ascertaining what part worms may have played in the burial of these extensive remains4 ,but the circumstances were not favourable for this object1 as the ruins are surrounded on three sides by rather steep banks1 down which earth is washed during rainy weather4 ,moreover most of the old rooms have been covered with roofs1 for the protection of the elegant tesselated pavements4 ,a few facts may1 however1 be given on the thickness of the soil over these ruins4 ,close outside the northern rooms there is a broken wall1 the summit of which was covered by #e inches of black mould2 and in a hole dug on the outer side of this wall1 where the ground had never before been disturbed1 black mould1 full of stones1 #bf inches in thickness1 was found1 resting on the undisturbed sub-soil of yellow clay4 ,at a depth of #bb inches from the surface a pig's jaw and a fragment of a tile were found4 ,when the excavations were first made1 some large trees grew over the ruins2 and the stump of one has been left directly over a party-wall near the bath-room1 for the sake of showing the thickness of the superincumbent soil1 which was here #ch inches4 ,in one small room1 which1 after being cleared out1 had not been roofed over1 my sons observed the hole of a worm passing through the rotten concrete1 and a living worm was found within the concrete4 ,in another open room worm-castings were seen on the floor1 over which some earth had by this means been deposited1 and here grass now grew4 ,brading1 ,isle of ,wight4--,a fine ,roman villa was discovered here in #ahhj2 and by the end of ,october no less than #ah chambers had been more or less cleared4 ,a coin dated #ccg ,a4,d4 was found4 ,my son ,william visited the place before the excavations were completed2 and he informs me that most of the floors were at first covered with much rubbish and fallen stones1 having their interstices completely filled up with mould1 abounding1 as the workmen said1 with worms1 above which there was mould without any stones4 ,the whole mass was in most places from #c to above #d ft4 in thickness4 ,in one very large room the overlying earth was only #b ft4 #f in4 thick2 and after this had been removed1 so many castings were thrown up between the tiles that the surface had to be almost daily swept4 ,most of the floors were fairly level4 ,the tops of the broken-down walls were covered in some places by only #d or #e inches of soil1 so that they were occasionally struck by the plough1 but in other places they were covered by from #ac to #ah inches of soil4 ,it is not probable that these walls could have been undermined by worms and subsided1 as they rested on a foundation of very hard red sand1 into which worms could hardly burrow4 ,the mortar1 however1 between the stones of the walls of a hypocaust was found by my son to have been penetrated by many worm-burrows4 ,the remains of this villa stand on land which slopes at an angle of about #c2 and the land appears to have been long cultivated4 ,therefore no doubt a considerable quantity of fine earth has been washed down from the upper parts of the field1 and has largely aided in the burial of these remains4 ,silchester1 ,hampshire4--,the ruins of this small ,roman town have been better preserved than any other remains of the kind in ,england4 ,a broken wall1 in most parts from #ae to #ah feet in height and about #a mile in compass1 now surrounds a space of about #ajj acres of cultivated land1 on which a farm-house and a church stand4 #ahg ,formerly1 when the weather was dry1 the lines of the buried walls could be traced by the appearance of the crops2 and recently very extensive excavations have been undertaken by the ,duke of ,wellington1 under the superintendence of the late ,rev4 ,j4 ,g4 ,joyce1 by which means many large buildings have been discovered4 ,mr4 ,joyce made careful coloured sections1 and measured the thickness of each bed of rubbish1 whilst the excavations were in progress2 and he has had the kindness to send me copies of several of them4 ,when my sons ,francis and ,horace visited these ruins1 he accompanied them1 and added his notes to theirs4 ,mr4 ,joyce estimates that the town was inhabited by the ,romans for about three centuries2 and no doubt much matter must have accumulated within the walls during this long period4 ,it appears to have been destroyed by fire1 and most of the stones used in the buildings have since been carried away4 ,these circumstances are unfavourable for ascertaining the part which worms have played in the burial of the ruins2 but as careful sections of the rubbish overlying an ancient town have seldom or never before been made in ,england1 ,i will give copies of the most characteristic portions of some of those made by ,mr4 ,joyce4 ,they are of too great length to be here introduced entire4 ,an east and west section1 #cj ft4 in length1 was made across a room in the ,basilica1 now called the ,hall of the ,merchants 7,fig4 #i74 ,the hard concrete floor1 still covered here and there with tesser1 was found at #c ft4 beneath the surface of the field1 which was here level4 ,on the floor there were two large piles of charred wood1 one alone of which is shown in the part of the section here given4 ,this pile was covered by a thin white layer of decayed stucco or plaster1 above which was a mass1 presenting a singularly disturbed appearance1 of broken tiles1 mortar1 rubbish and fine gravel1 together #bg inches in thickness4 ,mr4 ,joyce believes that the gravel was used in making the mortar or concrete1 which has since decayed1 some of the lime probably having been dissolved4 ,the disturbed state of the rubbish may have been due to its having been searched for building stones4 ,this bed was capped by fine vegetable mould1 #i inches in thickness4 ,from these facts we may conclude that the ,hall was burnt down1 and that much rubbish fell on the floor1 through and from which the worms slowly brought up the mould1 now forming the surface of the level field4 ,picture3 ,fig4 #g3 ,section through one of the fallen ,druidical stones at ,stonehenge4 ,fig4 #i3 ,section within a room in the ,basilica at ,silchester ,a section across the middle of another hall in the ,basilica1 #cb feet #f inches in length1 called the rarium1 is shown in ,fig4 #aj4 ,it appears that we have here evidence of two fires1 separated by an interval of time1 during which the #f inches of 8mortar and concrete with broken tiles0 was accumulated4 ,beneath one of the layers of charred wood1 a valuable relic1 a bronze eagle1 was found2 and this shows that the soldiers must have deserted the place in a panic4 ,owing to the death of ,mr4 ,joyce1 ,i have not been able to ascertain beneath which of the two layers the eagle was found4 ,the bed of rubble overlying the undisturbed gravel originally formed1 as ,i suppose1 the floor1 for it stands on a level with that of a corridor1 outside the walls of the ,hall2 but the corridor is not shown in the section as here given4 ,the vegetable mould was #af inches thick in the thickest part2 and the depth from the surface of the field1 clothed with herbage1 to the undisturbed gravel1 was #dj inches4 ,picture3 ,fig4 #aj3 ,section within a hall in the ,basilica of ,silchester ,the section shown in ,fig4 #aa represents an excavation made in the middle of the town1 and is here introduced because the bed of 8rich mould0 attained1 according to ,mr4 ,joyce1 the unusual thickness of #bj inches4 ,gravel lay at the depth of #dh inches from the surface2 but it was not ascertained whether this was in its natural state1 or had been brought here and had been rammed down1 as occurs in some other places4 ,picture3 ,fig4 #aa3 ,section in a block of buildings in the middle of the town of ,silchester ,the section shown in ,fig4 #ab was taken in the centre of the ,basilica1 and though it was #e feet in depth1 the natural sub-soil was not reached4 ,the bed marked 8concrete0 was probably at one time a floor2 and the beds beneath seem to be the remnants of more ancient buildings4 ,the vegetable mould was here only #i inches thick4 ,in some other sections1 not copied1 we likewise have evidence of buildings having been erected over the ruins of older ones4 ,in one case there was a layer of yellow clay of very unequal thickness between two beds of dbris1 the lower one of which rested on a floor with tesser4 ,the ancient broken walls appear to have been sometimes roughly cut down to a uniform level1 so as to serve as the foundations for a temporary building2 and ,mr4 ,joyce suspects that some of these buildings were wattled sheds1 plastered with clay1 which would account for the above-mentioned layer of clay4 ,picture3 ,fig4 #ab3 ,section in the centre of the ,basilica at ,silchester ,turning now to the points which more immediately concern us4 ,worm-castings were observed on the floors of several of the rooms1 in one of which the tesselation was unusually perfect4 ,the tesser here consisted of little cubes of hard sandstone of about #a inch1 several of which were loose or projected slightly above the general level4 ,one or occasionally two open worm-burrows were found beneath all the loose tesser4 ,worms have also penetrated the old walls of these ruins4 ,a wall1 which had just been exposed to view during the excavations then in progress1 was examined2 it was built of large flints1 and was #ah inches in thickness4 ,it appeared sound1 but when the soil was removed from beneath1 the mortar in the lower part was found to be so much decayed that the flints fell apart from their own weight4 ,here1 in the middle of the wall1 at a depth of #bi inches beneath the old floor and of #di inches beneath the surface of the field1 a living worm was found1 and the mortar was penetrated by several burrows4 ,a second wall was exposed to view for the first time1 and an open burrow was seen on its broken summit4 ,by separating the flints this burrow was traced far down in the interior of the wall2 but as some of the flints cohered firmly1 the whole mass was disturbed in pulling down the wall1 and the burrow could not be traced to the bottom4 ,the foundations of a third wall1 which appeared quite sound1 lay at a depth of #d feet beneath one of the floors1 and of course at a considerably greater depth beneath the level of the ground4 ,a large flint was wrenched out of the wall at about a foot from the base1 and this required much force1 as the mortar was sound2 but behind the flint in the middle of the wall1 the mortar was friable1 and here there were worm-burrows4 ,mr4 ,joyce and my sons were surprised at the blackness of the mortar in this and in several other cases1 and at the presence of mould in the interior of the walls4 ,some may have been placed there by the old builders instead of mortar2 but we should remember that worms line their burrows with black humus4 ,moreover open spaces would almost certainly have been occasionally left between the large irregular flints2 and these spaces1 we may feel sure1 would be filled up by the worms with their castings1 as soon as they were able to penetrate the wall4 ,rain-water1 oozing down the burrows would also carry fine dark-coloured particles into every crevice4 ,mr4 ,joyce was at first very sceptical about the amount of work which ,i attributed to worms2 but he ends his notes with reference to the last-mentioned wall by saying1 8,this case caused me more surprise and brought more conviction to me than any other4 ,i should have said1 and did say1 that it was quite impossible such a wall could have been penetrated by earth-worms40 ,in almost all the rooms the pavement has sunk considerably1 especially towards the middle2 and this is shown in the three following sections4 ,the measurements were made by stretching a string tightly and horizontally over the floor4 ,the section1 ,fig4 #ac1 was taken from north to south across a room1 #ah feet #d inches in length1 with a nearly perfect pavement1 next to the 8,red ,wooden ,hut40 ,in the northern half1 the subsidence amounted to #e inches beneath the level of the floor as it now stands close to the walls2 and it was greater in the northern than in the southern half2 but1 according to ,mr4 ,joyce1 the entire pavement has obviously subsided4 ,in several places1 the tesser appeared as if drawn a little away from the walls2 whilst in other places they were still in close contact with them4 ,picture3 ,fig4 #ad3 ,a north and south section through the subsided floor of a corridor ,in ,fig4 #ad1 we see a section across the paved floor of the southern corridor or ambulatory of a quadrangle1 in an excavation made near 8,the ,spring40 ,the floor is #g feet #i inches wide1 and the broken-down walls now project only of an inch above its level4 ,the field1 which was in pasture1 here sloped from north to south1 at an angle of #cj1 #dj4 ,the nature of the ground at some little distance on each side of the corridor is shown in the section4 ,it consisted of earth full of stones and other dbris1 capped with dark vegetable mould which was thicker on the lower or southern than on the northern side4 ,the pavement was nearly level along lines parallel to the side-walls1 but had sunk in the middle as much as #g inches4 ,a small room at no great distance from that represented in ,fig4 #ac1 had been enlarged by the ,roman occupier on the southern side1 by an addition of #e feet #d inches in breadth4 ,for this purpose the southern wall of the house had been pulled down1 but the foundations of the old wall had been left buried at a little depth beneath the pavement of the enlarged room4 ,mr4 ,joyce believes that this buried wall must have been built before the reign of ,claudius ,,ii41 who died #bgj ,a4,d4 ,we see in the accompanying section1 ,fig4 #ae1 that the tesselated pavement has subsided to a less degree over the buried wall than elsewhere2 so that a slight convexity or protuberance here stretched in a straight line across the room4 ,this led to a hole being dug1 and the buried wall was thus discovered4 ,picture3 ,fig4 #ae3 ,section through the subsided floor ,we see in these three sections1 and in several others not given1 that the old pavements have sunk or sagged considerably4 ,mr4 ,joyce formerly attributed this sinking solely to the slow settling of the ground4 ,that there has been some settling is highly probable1 and it may be seen in ,fig4 #ae that the pavement for a width of #e feet over the southern enlargement of the room1 which must have been built on fresh ground1 has sunk a little more than on the old northern side4 ,but this sinking may possibly have had no connection with the enlargement of the room2 for in ,fig4 #ac one half of the pavement has subsided more than the other half without any assignable cause4 ,in a bricked passage to ,mr4 ,joyce's own house1 laid down only about six years ago1 the same kind of sinking has occurred as in the ancient buildings4 ,nevertheless it does not appear probable that the whole amount of sinking can be thus accounted for4 ,the ,roman builders excavated the ground to an unusual depth for the foundations of their walls1 which were thick and solid2 it is therefore hardly credible that they should have been careless about the solidity of the bed on which their tesselated and often ornamented pavements were laid4 ,the sinking must1 as it appears to me1 be attributed in chief part to the pavement having been undermined by worms1 which we know are still at work4 ,even ,mr4 ,joyce at last admitted that this could not have failed to have produced a considerable effect4 ,thus also the large quantity of fine mould overlying the pavements can be accounted for1 the presence of which would otherwise be inexplicable4 ,my sons noticed that in one room in which the pavement had sagged very little1 there was an unusually small amount of overlying mould4 ,as the foundations of the walls generally lie at a considerable depth1 they will either have not subsided at all through the undermining action of worms1 or they will have subsided much less than the floor4 ,this latter result would follow from worms not often working deep down beneath the foundations2 but more especially from the walls not yielding when penetrated by worms1 whereas the successively formed burrows in a mass of earth1 equal to one of the walls in depth and thickness1 would have collapsed many times since the desertion of the ruins1 and would consequently have shrunk or subsided4 ,as the walls cannot have sunk much or at all1 the immediately adjoining pavement from adhering to them will have been prevented from subsiding2 and thus the present curvature of the pavement is intelligible4 ,the circumstance which has surprised me most with respect to ,silchester is that during the many centuries which have elapsed since the old buildings were deserted1 the vegetable mould has not accumulated over them to a greater thickness than that here observed4 ,in most places it is only about #i inches in thickness1 but in some places #ab or even more inches4 ,in ,fig4 #aa1 it is given as #bj inches1 but this section was drawn by ,mr4 ,joyce before his attention was particularly called to this subject4 ,the land enclosed within the old walls is described as sloping slightly to the south2 but there are parts which1 according to ,mr4 ,joyce1 are nearly level1 and it appears that the mould is here generally thicker than elsewhere4 ,the surface slopes in other parts from west to east1 and ,mr4 ,joyce describes one floor as covered at the western end by rubbish and mould to a thickness of #bh inches1 and at the eastern end by a thickness of only #aa inches4 ,a very slight slope suffices to cause recent castings to flow downwards during heavy rain1 and thus much earth will ultimately reach the neighbouring rills and streams and be carried away4 ,by this means1 the absence of very thick beds of mould over these ancient ruins may1 as ,i believe1 be explained4 ,moreover most of the land here has long been ploughed1 and this would greatly aid the washing away of the finer earth during rainy weather4 ,the nature of the beds immediately beneath the vegetable mould in some of the sections is rather perplexing4 ,we see1 for instance1 in the section of an excavation in a grass meadow 7,fig4 #ad71 which sloped from north to south at an angle of #c #dj1 that the mould on the upper side is only six inches and on the lower side nine inches in thickness4 ,but this mould lies on a mass 7#be inches in thickness on the upper side7 8of dark brown mould10 as described by ,mr4 ,joyce1 8thickly interspersed with small pebbles and bits of tiles1 which present a corroded or worn appearance40 ,the state of this dark-coloured earth is like that of a field which has long been ploughed1 for the earth thus becomes intermingled with stones and fragments of all kinds which have been much exposed to the weather4 ,if during the course of many centuries this grass meadow and the other now cultivated fields have been at times ploughed1 and at other times left as pasture1 the nature of the ground in the above section is rendered intelligible4 ,for worms will continually have brought up fine earth from below1 which will have been stirred up by the plough whenever the land was cultivated4 ,but after a time a greater thickness of fine earth will thus have been accumulated than could be reached by the plough2 and a bed like the #be-;inch mass1 in ,fig4 #ad1 will have been formed beneath the superficial mould1 which latter will have been brought to the surface within more recent times1 and have been well sifted by the worms4 ,wroxeter1 ,shropshire4--,the old ,roman city of ,uriconium was founded in the early part of the second century1 if not before this date2 and it was destroyed1 according to ,mr4 ,wright1 probably between the middle of the fourth and fifth century4 ,the inhabitants were massacred1 and skeletons of women were found in the hypocausts4 ,before the year #ahei1 the sole remnant of the city above ground1 was a portion of a massive wall about #bj ft4 in height4 ,the surrounding land undulates slightly1 and has long been under cultivation4 ,it had been noticed that the corn-crops ripened prematurely in certain narrow lines1 and that the snow remained unmelted in certain places longer than in others4 ,these appearances led1 as ,i was informed1 to extensive excavations being undertaken4 ,the foundations of many large buildings and several streets have thus been exposed to view4 ,the space enclosed within the old walls is an irregular oval1 about #a mile in length4 ,many of the stones or bricks used in the buildings must have been carried away2 but the hypocausts1 baths1 and other underground buildings were found tolerably perfect1 being filled with stones1 broken tiles1 rubbish and soil4 ,the old floors of various rooms were covered with rubble4 ,as ,i was anxious to know how thick the mantle of mould and rubbish was1 which had so long concealed these ruins1 ,i applied to ,dr4 ,h4 ,johnson1 who had superintended the excavations2 and he1 with the greatest kindness1 twice visited the place to examine it in reference to my questions1 and had many trenches dug in four fields which had hitherto been undisturbed4 ,the results of his observations are given in the following ,table4 ,he also sent me specimens of the mould1 and answered1 as far as he could1 all my questions4 ,,measurements ,,by ,,dr4 ,h4 ,,johnson ,,of ,,the ,,thickness ,,of ,,the ,,vegetable ,,mould ,,over ,,the ,,roman ,,ruins ,,at ,,wroxeter4 ,trenches dug in a field called 8,old ,works40 ,thickness of mould in inches4 #a4 ,at a depth of #cf inches #bj undisturbed sand was reached #b4 ,at a depth of #cc inches #ba concrete was reached #c4 ,at a depth of #i inches #i concrete was reached ,trenches dug in a field called 8,shop ,leasows20 this is the highest field within the old walls1 and slopes down from a sub-central point on all sides at about an angle of #b4 ,thickness of mould in inches4 #d4 ,summit of field1 trench #de #dj inches deep #e4 ,close to summit of field1 #bf trench #cf inches deep #f4 ,close to summit of field1 #bh trench #bh inches deep #g4 ,near summit of field1 trench #bd #cf inches deep #h4 ,near summit of field1 trench #bd at one end #ci inches deep2 the mould here graduated into the underlying undisturbed sand1 and its thickness 7#bd inches7 is somewhat arbitrary4 ,at the other end of the trench1 a causeway was encountered at a depth of only #g inches1 and the mould was here only #g inches thick #i4 ,trench close to the last1 #bh #bd inches in depth #aj4 ,lower part of same field1 #ae trench #cj inches deep #aa4 ,lower part of same field1 #ag trench #ca inches deep #ab4 ,lower part of same field1 #bh trench #cf inches deep1 at which depth undisturbed sand was reached #ac4 ,in another part of same #i field1 trench #i inches deep stopped by concrete #ad4 ,in another part of same #i field1 trench #i inches deep1 stopped by concrete #ae4 ,in another part of the same #af field1 trench #bd inches deep1 when sand was reached #af4 ,in another part of same #ac field1 trench #cj inches deep1 when stones were reached2 at one end of the trench mould #ab inches1 at the other end #ad inches thick ,small field between 8,old ,works0 and 8,shop ,leasows10 ,i believe nearly as high as the upper part of the latter field4 ,thickness of mould in inches4 #ag4 ,trench #bf inches deep #bd #ah4 ,trench #aj inches deep1 and #aj then came upon a causeway #ai4 ,trench #cd inches deep #cj #bj4 ,trench #ca inches deep #ca ,field on the western side of the space enclosed within the old walls4 ,thickness of mould in inches4 #ba4 ,trench #bh inches deep1 when #af undisturbed sand was reached #bb4 ,trench #bi inches deep1 when #ae undisturbed sand was reached #bc4 ,trench #ad inches deep1 and #ad then came upon a building ,dr4 ,johnson distinguished as mould the earth which differed1 more or less abruptly1 in its dark colour and in its texture from the underlying sand or rubble4 ,in the specimens sent to me1 the mould resembled that which lies immediately beneath the turf in old pasture-land1 excepting that it often contained small stones1 too large to have passed through the bodies of worms4 ,but the trenches above described were dug in fields1 none of which were in pasture1 and all had been long cultivated4 ,bearing in mind the remarks made in reference to ,silchester on the effects of long-continued culture1 combined with the action of worms in bringing up the finer particles to the surface1 the mould1 as so designated by ,dr4 ,johnson1 seems fairly well to deserve its name4 ,its thickness1 where there was no causeway1 floor or walls beneath1 was greater than has been elsewhere observed1 namely1 in many places above #b ft41 and in one spot above #c ft4 ,the mould was thickest on and close to the nearly level summit of the field called 8,shop ,leasows10 and in a small adjoining field1 which1 as ,i believe1 is of nearly the same height4 ,one side of the former field slopes at an angle of rather above #b1 and ,i should have expected that the mould1 from being washed down during heavy rain1 would have been thicker in the lower than in the upper part2 but this was not the case in two out of the three trenches here dug4 ,in many places1 where streets ran beneath the surface1 or where old buildings stood1 the mould was only #h inches in thickness2 and ,dr4 ,johnson was surprised that in ploughing the land1 the ruins had never been struck by the plough as far as he had heard4 ,he thinks that when the land was first cultivated the old walls were perhaps intentionally pulled down1 and that hollow places were filled up4 ,this may have been the case2 but if after the desertion of the city the land was left for many centuries uncultivated1 worms would have brought up enough fine earth to have covered the ruins completely2 that is if they had subsided from having been undermined4 ,the foundations of some of the walls1 for instance those of the portion still standing about #bj feet above the ground1 and those of the marketplace1 lie at the extraordinary depth of #ad feet2 but it is highly improbable that the foundations were generally so deep4 ,the mortar employed in the buildings must have been excellent1 for it is still in parts extremely hard4 ,wherever walls of any height have been exposed to view1 they are1 as ,dr4 ,johnson believes1 still perpendicular4 ,the walls with such deep foundations cannot have been undermined by worms1 and therefore cannot have subsided1 as appears to have occurred at ,abinger and ,silchester4 ,hence it is very difficult to account for their being now completely covered with earth2 but how much of this covering consists of vegetable mould and how much of rubble ,i do not know4 ,the market-place1 with the foundations at a depth of #ad feet1 was covered up1 as ,dr4 ,johnson believes1 by between #f and #bd inches of earth4 ,the tops of the broken-down walls of a caldarium or bath1 #i feet in depth1 were likewise covered up with nearly #b feet of earth4 ,the summit of an arch1 leading into an ash-pit #g feet in depth1 was covered up with not more than #h inches of earth4 ,whenever a building which has not subsided is covered with earth1 we must suppose1 either that the upper layers of stone have been at some time carried away by man1 or that earth has since been washed down during heavy rain1 or blown down during storms1 from the adjoining land2 and this would be especially apt to occur where the land has long been cultivated4 ,in the above cases the adjoining land is somewhat higher than the three specified sites1 as far as ,i can judge by maps and from information given me by ,dr4 ,johnson4 ,if2 however1 a great pile of broken stones1 mortar1 plaster1 timber and ashes fell over the remains of any building1 their disintegration in the course of time1 and the sifting action of worms1 would ultimately conceal the whole beneath fine earth4 99 99 99 99 99 ,conclusion4--,the cases given in this chapter show that worms have played a considerable part in the burial and concealment of several ,roman and other old buildings in ,england2 but no doubt the washing down of soil from the neighbouring higher lands1 and the deposition of dust1 have together aided largely in the work of concealment4 ,dust would be apt to accumulate wherever old broken-down walls projected a little above the then existing surface and thus afforded some shelter4 ,the floors of the old rooms1 halls and passages have generally sunk1 partly from the settling of the ground1 but chiefly from having been undermined by worms2 and the sinking has commonly been greater in the middle than near the walls4 ,the walls themselves1 whenever their foundations do not lie at a great depth1 have been penetrated and undermined by worms1 and have consequently subsided4 ,the unequal subsidence thus caused1 probably explains the great cracks which may be seen in many ancient walls1 as well as their inclination from the perpendicular4 ,,chapter ,v4 ,,the ,,action ,,of ,,worms ,,in ,,the ,,denudation ,,of ,,the ,,land4 ,evidence of the amount of denudation which the land has undergone--,sub-aerial denudation--,the deposition of dust--,vegetable mould1 its dark colour and fine texture largely due to the action of worms--,the disintegration of rocks by the humus-acids--,similar acids apparently generated within the bodies of worms--,the action of these acids facilitated by the continued movement of the particles of earth--,a thick bed of mould checks the disintegration of the underlying soil and rocks4 ,particles of stone worn or triturated in the gizzards of worms--,swallowed stones serve as mill-stones--,the levigated state of the castings--,fragments of brick in the castings over ancient buildings well rounded4 ,the triturating power of worms not quite insignificant under a geological point of view4 ,,no one doubts that our world at one time consisted of crystalline rocks1 and that it is to their disintegration through the action of air1 water1 changes of temperature1 rivers1 waves of the sea1 earthquakes and volcanic outbursts1 that we owe our sedimentary formations4 ,these after being consolidated and sometimes recrystallized1 have often been again disintegrated4 ,denudation means the removal of such disintegrated matter to a lower level4 ,of the many striking results due to the modern progress of geology there are hardly any more striking than those which relate to denudation4 ,it was long ago seen that there must have been an immense amount of denudation2 but until the successive formations were carefully mapped and measured1 no one fully realised how great was the amount4 ,one of the first and most remarkable memoirs ever published on this subject was that by ,ramsay1 #baj who in #ahdf showed that in ,wales from #ijjj to #aa1jjj feet in thickness of solid rock had been stripped off large tracks of country4 ,perhaps the plainest evidence of great denudation is afforded by faults or cracks1 which extend for many miles across certain districts1 with the strata on one side raised even ten thousand feet above the corresponding strata on the opposite side2 and yet there is not a vestige of this gigantic displacement visible on the surface of the land4 ,a huge pile of rock has been planed away on one side and not a remnant left4 ,until the last twenty or thirty years1 most geologists thought that the waves of the sea were the chief agents in the work of denudation2 but we may now feel sure that air and rain1 aided by streams and rivers1 are much more powerful agents1--that is if we consider the whole area of the land4 ,the long lines of escarpment which stretch across several parts of ,england were formerly considered to be undoubtedly ancient coast-lines2 but we now know that they stand up above the general surface merely from resisting air1 rain and frost better than the adjoining formations4 ,it has rarely been the good fortune of a geologist to bring conviction to the minds of his fellow-workers on a disputed point by a single memoir2 but ,mr4 ,whitaker1 of the ,geological ,survey of ,england1 was so fortunate when1 in #ahfg1 he published his paper 8,on sub-aerial ,denudation1 and on ,cliffs and ,escarpments of the ,chalk40 #baa ,before this paper appeared1 ,mr4 ,a4 ,tylor had adduced important evidence on sub-aerial denudation1 by showing that the amount of matter brought down by rivers must infallibly lower the level of their drainage basins by many feet in no immense lapse of time4 ,this line of argument has since been followed up in the most interesting manner by ,archibald ,geikie1 ,croll and others1 in a series of valuable memoirs4 #bab ,for the sake of those who have never attended to this subject1 a single instance may be here given1 namely1 that of the ,mississippi1 which is chosen because the amount of sediment brought down by this great river has been investigated with especial care by order of the ,united ,states ,government4 ,the result is1 as ,mr4 ,croll shows1 that the mean level of its enormous area of drainage must be lowered #a_/deff of a foot annually1 or #a foot in #deff years4 ,consequently1 taking the best estimate of the mean height of the ,north ,american continent1 viz4 #gdh feet1 and looking to the future1 the whole of the great ,mississippi basin will be washed away1 and 8brought down to the sea-level in less than #d1ejj1jjj years1 if no elevation of the land takes place40 ,some rivers carry down much more sediment relatively to their size1 and some much less than the ,mississippi4 ,disintegrated matter is carried away by the wind as well as by running water4 ,during volcanic outbursts much rock is triturated and is thus widely dispersed2 and in all arid countries the wind plays an important part in the removal of such matter4 ,wind-driven sand also wears down the hardest rocks4 ,i have shown #bac that during four months of the year a large quantity of dust is blown from the north-western shores of ,africa1 and falls on the ,atlantic over a space of #afjj miles in latitude1 and for a distance of from #cjj to #fjj miles from the coast4 ,but dust has been seen to fall at a distance of #ajcj miles from the shores of ,africa4 ,during a stay of three weeks at ,st4 ,jago in the ,cape ,verde ,archipelago1 the atmosphere was almost always hazy1 and extremely fine dust coming from ,africa was continually falling4 ,in some of this dust which fell in the open ocean at a distance of between #ccj and #chj miles from the ,african coast1 there were many particles of stone1 about #a_/ajjj of an inch square4 ,nearer to the coast the water has been seen to be so much discoloured by the falling dust1 that a sailing vessel left a track behind her4 ,in countries1 like the ,cape ,verde ,archipelago1 where it seldom rains and there are no frosts1 the solid rock nevertheless disintegrates2 and in conformity with the views lately advanced by a distinguished ,belgian geologist1 ,de ,koninck1 such disintegration may be attributed in chief part to the action of the carbonic and nitric acids1 together with the nitrates and nitrites of ammonia1 dissolved in the dew4 ,in all humid1 even moderately humid1 countries1 worms aid in the work of denudation in several ways4 ,the vegetable mould which covers1 as with a mantle1 the surface of the land1 has all passed many times through their bodies4 ,mould differs in appearance from the subsoil only in its dark colour1 and in the absence of fragments or particles of stone 7when such are present in the subsoil71 larger than those which can pass through the alimentary canal of a worm4 ,this sifting of the soil is aided1 as has already been remarked1 by burrowing animals of many kinds1 especially by ants4 ,in countries where the summer is long and dry1 the mould in protected places must be largely increased by dust blown from other and more exposed places4 ,for instance1 the quantity of dust sometimes blown over the plains of ,la ,plata1 where there are no solid rocks1 is so great1 that during the 8gran seco10 #ahbg to #ahcj1 the appearance of the land1 which is here unenclosed1 was so completely changed that the inhabitants could not recognise the limits of their own estates1 and endless lawsuits arose4 ,immense quantities of dust are likewise blown about in ,egypt and in the south of ,france4 ,in ,china1 as ,richthofen maintains1 beds appearing like fine sediment1 several hundred feet in thickness and extending over an enormous area1 owe their origin to dust blown from the high lands of central ,asia4 #bae ,in humid countries like ,great ,britain1 as long as the land remains in its natural state clothed with vegetation1 the mould in any one place can hardly be much increased by dust2 but in its present condition1 the fields near high roads1 where there is much traffic1 must receive a considerable amount of dust1 and when fields are harrowed during dry and windy weather1 clouds of dust may be seen to be blown away4 ,but in all these cases the surface-soil is merely transported from one place to another4 ,the dust which falls so thickly within our houses consists largely of organic matter1 and if spread over the land would in time decay and disappear almost entirely4 ,it appears1 however1 from recent observations on the snow-fields of the ,arctic regions1 that some little meteoric dust of extra mundane origin is continually falling4 ,the dark colour of ordinary mould is obviously due to the presence of decaying organic matter1 which1 however1 is present in but small quantities4 ,the loss of weight which mould suffers when heated to redness seems to be in large part due to water in combination being dispelled4 ,in one sample of fertile mould the amount of organic matter was ascertained to be only #a4gf per cent42 in some artificially prepared soil it was as much as #e4e per cent41 and in the famous black soil of ,russia from #e to even #ab per cent4 #bag;a ,in leaf-mould formed exclusively by the decay of leaves the amount is much greater1 and in peat the carbon alone sometimes amounts to #fd per cent42 but with these latter cases we are not here concerned4 ,the carbon in the soil tends gradually to oxidise and to disappear1 except where water accumulates and the climate is cool2 #bag;b so that in the oldest pasture-land there is no great excess of organic matter1 notwithstanding the continued decay of the roots and the underground stems of plants1 and the occasional addition of manure4 ,the disappearance of the organic matter from mould is probably much aided by its being brought again and again to the surface in the castings of worms4 ,worms1 on the other hand1 add largely to the organic matter in the soil by the astonishing number of half-decayed leaves which they draw into their burrows to a depth of #b or #c inches4 ,they do this chiefly for obtaining food1 but partly for closing the mouths of their burrows and for lining the upper part4 ,the leaves which they consume are moistened1 torn into small shreds1 partially digested1 and intimately commingled with earth2 and it is this process which gives to vegetable mould its uniform dark tint4 ,it is known that various kinds of acids are generated by the decay of vegetable matter2 and from the contents of the intestines of worms and from their castings being acid1 it seems probable that the process of digestion induces an analogous chemical change in the swallowed1 triturated1 and half-decayed leaves4 ,the large quantity of carbonate of lime secreted by the calciferous glands apparently serves to neutralise the acids thus generated2 for the digestive fluid of worms will not act unless it be alkaline4 ,as the contents of the upper part of their intestines are acid1 the acidity can hardly be due to the presence of uric acid4 ,we may therefore conclude that the acids in the alimentary canal of worms are formed during the digestive process2 and that probably they are nearly of the same nature as those in ordinary mould or humus4 ,the latter are well known to have the power of de-oxidising or dissolving per-oxide of iron1 as may be seen wherever peat overlies red sand1 or where a rotten root penetrates such sand4 ,now ,i kept some worms in a pot filled with very fine reddish sand1 consisting of minute particles of silex coated with the red oxide of iron2 and the burrows1 which the worms made through this sand1 were lined or coated in the usual manner with their castings1 formed of the sand mingled with their intestinal secretions and the refuse of the digested leaves2 and this sand had almost wholly lost its red colour4 ,when small portions of it were placed under the microscope1 most of the grains were seen to be transparent and colourless1 owing to the dissolution of the oxide2 whilst almost all the grains taken from other parts of the pot were coated with the oxide4 ,acetic acid produced hardly any effect on his sand2 and even hydrochloric1 nitric and sulphuric acids1 diluted as in the ,pharmacopoeia1 produced less effect than did the acids in the intestines of the worms4 ,mr4 ,a4 ,a4 ,julien has lately collected all the extant information about the acids generated in humus1 which1 according to some chemists1 amount to more than a dozen different kinds4 ,these acids1 as well as their acid salts 7i4e41 in combination with potash1 soda1 and ammonia71 act energetically on carbonate of lime and on the oxides of iron4 ,it is also known that some of these acids1 which were called long ago by ,thnard azohumic1 are enabled to dissolve colloid silica in proportion to the nitrogen which they contain4 #bbj ,in the formation of these latter acids worms probably afford some aid1 for ,dr4 ,h4 ,johnson informs me that by ,nessler's test he found #j4jah per cent4 of ammonia in their castings4 ,it may be here added that ,i have recently been informed by ,dr4 ,gilbert 8that several square yards on his lawn were swept clean1 and after two or three weeks all the worm-castings on the space were collected and dried4 ,these were found to contain #j4ce of nitrogen4 ,this is from two to three times as much as we find in our ordinary arable surface-soil2 more than in our ordinary pasture surface-soil2 but less than in rich kitchen-garden mould4 ,supposing a quantity of castings equal to #aj tons in the dry state were annually deposited on an acre1 this would represent a manuring of #gh lbs4 of nitrogen per acre per annum2 and this is very much more than the amount of nitrogen in the annual yield of hay per acre1 if raised without any nitrogenous manure4 ,obviously1 so far as the nitrogen in the castings is derived from surface-growth or from surface-soil1 it is not a gain to the latter2 but so far as it is derived from below1 it is a gain40 ,the several humus-acids1 which appear1 as we have just seen1 to be generated within the bodies of worms during the digestive process1 and their acid salts1 play a highly important part1 according to the recent observations of ,mr4 ,julien1 in the disintegration of various kinds of rocks4 ,it has long been known that the carbonic acid1 and no doubt nitric and nitrous acids1 which are present in rain-water1 act in like manner4 ,there is1 also1 a great excess of carbonic acid in all soils1 especially in rich soils1 and this is dissolved by the water in the ground4 ,the living roots of plants1 moreover1 as ,sachs and others have shown1 quickly corrode and leave their impressions on polished slabs of marble1 dolomite and phosphate of lime4 ,they will attack even basalt and sandstone4 #bbb ,but we are not here concerned with agencies which are wholly independent of the action of worms4 ,the combination of any acid with a base is much facilitated by agitation1 as fresh surfaces are thus continually brought into contact4 ,this will be thoroughly effected with the particles of stone and earth in the intestines of worms1 during the digestive process2 and it should be remembered that the entire mass of the mould over every field1 passes1 in the course of a few years1 through their alimentary canals4 ,moreover as the old burrows slowly collapse1 and as fresh castings are continually brought to the surface1 the whole superficial layer of mould slowly revolves or circulates2 and the friction of the particles one with another will rub off the finest films of disintegrated matter as soon as they are formed4 ,through these several means1 minute fragments of rocks of many kinds and mere particles in the soil will be continually exposed to chemical decomposition2 and thus the amount of soil will tend to increase4 ,as worms line their burrows with their castings1 and as the burrows penetrate to a depth of #e or #f1 or even more feet1 some small amount of the humus-acids will be carried far down1 and will there act on the underlying rocks and fragments of rock4 ,thus the thickness of the soil1 if none be removed from the surface1 will steadily though slowly tend to increase2 but the accumulation will after a time delay the disintegration of the underlying rocks and of the more deeply seated particles4 ,for the humus-acids which are generated chiefly in the upper layer of vegetable mould1 are extremely unstable compounds1 and are liable to decomposition before they reach any considerable depth4 #bbc ,a thick bed of overlying soil will also check the downward extension of great fluctuations of temperature1 and in cold countries will check the powerful action of frost4 ,the free access of air will likewise be excluded4 ,from these several causes disintegration would be almost arrested1 if the overlying mould were to increase much in thickness1 owing to none or little being removed from the surface4 #bbd;a ,in my own immediate neighbourhood we have a curious proof how effectually a few feet of clay checks some change which goes on in flints1 lying freely exposed2 for the large ones which have lain for some time on the surface of ploughed fields cannot be used for building2 they will not cleave properly1 and are said by the workmen to be rotten4 #bbd;b ,it is therefore necessary to obtain flints for building purposes from the bed of red clay overlying the chalk 7the residue of its dissolution by rain-water7 or from the chalk itself4 ,not only do worms aid directly in the chemical disintegration of rocks1 but there is good reason to believe that they likewise act in a direct and mechanical manner on the smaller particles4 ,all the species which swallow earth are furnished with gizzards2 and these are lined with so thick a chitinous membrane1 that ,perrier speaks of it1 #bbe;a as 8une vritable armature40 ,the gizzard is surrounded by powerful transverse muscles1 which1 according to ,claparde1 are about ten times as thick as the longitudinal ones2 and ,perrier saw them contracting energetically4 ,worms belonging to one genus1 ,digaster1 have two distinct but quite similar gizzards2 and in another genus1 ,moniligaster1 the second gizzard consists of four pouches1 one succeeding the other1 so that it may almost be said to have five gizzards4 #bbe;b ,in the same manner as gallinaceous and struthious birds swallow stones to aid in the trituration of their food1 so it appears to be with terricolous worms4 ,the gizzards of thirty-eight of our common worms were opened1 and in twenty-five of them small stones or grains of sand1 sometimes together with the hard calcareous concretions formed within the anterior calciferous glands1 were found1 and in two others concretions alone4 ,in the gizzards of the remaining worms there were no stones2 but some of these were not real exceptions1 as the gizzards were opened late in the autumn1 when the worms had ceased to feed and their gizzards were quite empty4 #bbf ,when worms make their burrows through earth abounding with little stones1 no doubt many will be unavoidably swallowed2 but it must not be supposed that this fact accounts for the frequency with which stones and sand are found in their gizzards4 ,for beads of glass and fragments of brick and of hard tiles were scattered over the surface of the earth1 in pots in which worms were kept and had already made their burrows2 and very many of these beads and fragments were picked up and swallowed by the worms1 for they were found in their castings1 intestines1 and gizzards4 ,they even swallowed the coarse red dust1 formed by the pounding of the tiles4 ,nor can it be supposed that they mistook the beads and fragments for food2 for we have seen that their taste is delicate enough to distinguish between different kinds of leaves4 ,it is therefore manifest that they swallow hard objects1 such as bits of stone1 beads of glass and angular fragments of bricks or tiles for some special purpose2 and it can hardly be doubted that this is to aid their gizzards in crushing and grinding the earth1 which they so largely consume4 ,that such hard objects are not necessary for crushing leaves1 may be inferred from the fact that certain species1 which live in mud or water and feed on dead or living vegetable matter1 but which do not swallow earth1 are not provided with gizzards1 #bbg and therefore cannot have the power of utilising stones4 ,during the grinding process1 the particles of earth must be rubbed against one another1 and between the stones and the tough lining membrane of the gizzard4 ,the softer particles will thus suffer some attrition1 and will perhaps even be crushed4 ,this conclusion is supported by the appearance of freshly ejected castings1 for these often reminded me of the appearance of paint which has just been ground by a workman between two flat stones4 ,morren remarks that the intestinal canal is 8impleta tenuissim terr1 veluti in pulverem redact40 #bbh;a ,perrier also speaks of 8l'tat de pte excessivement fine laquelle est rduite la terre qu'ils rejettent10 c4 #bbh;b ,as the amount of trituration which the particles of earth undergo in the gizzards of worms possesses some interest 7as we shall hereafter see71 ,i endeavoured to obtain evidence on this head by carefully examining many of the fragments which had passed through their alimentary canals4 ,with worms living in a state of nature1 it is of course impossible to know how much the fragments may have been worn before they were swallowed4 ,it is1 however1 clear that worms do not habitually select already rounded particles1 for sharply angular bits of flint and of other hard rocks were often found in their gizzards or intestines4 ,on three occasions sharp spines from the stems of rose-bushes were thus found4 ,worms kept in confinement repeatedly swallowed angular fragments of hard tile1 coal1 cinders1 and even the sharpest fragments of glass4 ,gallinaceous and struthious birds retain the same stones in their gizzards for a long time1 which thus become well rounded2 but this does not appear to be the case with worms1 judging from the large number of the fragments of tiles1 glass beads1 stones1 c41 commonly found in their castings and intestines4 ,so that unless the same fragments were to pass repeatedly through their gizzards1 visible signs of attrition in the fragments could hardly be expected1 except perhaps in the case of very soft stones4 ,i will now give such evidence of attrition as ,i have been able to collect4 ,in the gizzards of some worms dug out of a thin bed of mould over the chalk1 there were many well-rounded small fragments of chalk1 and two fragments of the shells of a land-mollusc 7as ascertained by their microscopical structure71 which latter were not only rounded but somewhat polished4 ,the calcareous concretions formed in the calciferous glands1 which are often found in their gizzards1 intestines1 and occasionally in their castings1 when of large size1 sometimes appeared to have been rounded2 but with all calcareous bodies the rounded appearance may be partly or wholly due to their corrosion by carbonic acid and the humus-acids4 ,in the gizzards of several worms collected in my kitchen garden near a hothouse1 eight little fragments of cinders were found1 and of these1 six appeared more or less rounded1 as were two bits of brick2 but some other bits were not at all rounded4 ,a farm-road near ,abinger ,hall had been covered seven years before with brick-rubbish to the depth of about #f inches2 turf had grown over this rubbish on both sides of the road for a width of #ah inches1 and on this turf there were innumerable castings4 ,some of them were coloured of a uniform red owing to the presence of much brick-dust1 and they contained many particles of brick and of hard mortar from #a to #c mm4 in diameter1 most of which were plainly rounded2 but all these particles may have been rounded before they were protected by the turf and were swallowed1 like those on the bare parts of the road which were much worn4 ,a hole in a pasture-field had been filled up with brick-rubbish at the same time1 viz41 seven years ago1 and was now covered with turf2 and here the castings contained very many particles of brick1 all more or less rounded2 and this brick-rubbish1 after being shot into the hole1 could not have undergone any attrition4 ,again1 old bricks very little broken1 together with fragments of mortar1 were laid down to form walks1 and were then covered with from #d to #f inches of gravel2 six little fragments of brick were extracted from castings collected on these walks1 three of which were plainly worn4 ,there were also very many particles of hard mortar1 about half of which were well rounded2 and it is not credible that these could have suffered so much corrosion from the action of carbonic acid in the course of only seven years4 ,much better evidence of the attrition of hard objects in the gizzards of worms1 is afforded by the state of the small fragments of tiles or bricks1 and of concrete in the castings thrown up where ancient buildings once stood4 ,as all the mould covering a field passes every few years through the bodies of worms1 the same small fragments will probably be swallowed and brought to the surface many times in the course of centuries4 ,it should be premised that in the several following cases1 the finer matter was first washed away from the castings1 and then all the particles of bricks1 tiles and concrete were collected without any selection1 and were afterwards examined4 ,now in the castings ejected between the tesser on one of the buried floors of the ,roman villa at ,abinger1 there were many particles 7from to #b mm4 in diameter7 of tiles and concrete1 which it was impossible to look at with the naked eye or through a strong lens1 and doubt for a moment that they had almost all undergone much attrition4 ,i speak thus after having examined small water-worn pebbles1 formed from ,roman bricks1 which ,m4 ,henri de ,saussure had the kindness to send me1 and which he had extracted from sand and gravel beds1 deposited on the shores of the ,lake of ,geneva1 at a former period when the water stood at about two metres above its present level4 ,the smallest of these water-worn pebbles of brick from ,geneva resembled closely many of those extracted from the gizzards of worms1 but the larger ones were somewhat smoother4 ,four castings found on the recently uncovered1 tesselated floor of the great room in the ,roman villa at ,brading1 contained many particles of tile or brick1 of mortar1 and of hard white cement2 and the majority of these appeared plainly worn4 ,the particles of mortar1 however1 seemed to have suffered more corrosion than attrition1 for grains of silex often projected from their surfaces4 ,castings from within the nave of ,beaulieu ,abbey1 which was destroyed by ,henry ,,viii41 were collected from a level expanse of turf1 overlying the buried tesselated pavement1 through which worm-burrows passed2 and these castings contained innumerable particles of tiles and bricks1 of concrete and cement1 the majority of which had manifestly undergone some or much attrition4 ,there were also many minute flakes of a micaceous slate1 the points of which were rounded4 ,if the above supposition1 that in all these cases the same minute fragments have passed several times through the gizzards of worms1 be rejected1 notwithstanding its inherent probability1 we must then assume that in all the above cases the many rounded fragments found in the castings had all accidentally undergone much attrition before they were swallowed2 and this is highly improbable4 ,on the other hand it must be stated that fragments of ornamental tiles1 somewhat harder than common tiles or bricks1 which had been swallowed only once by worms kept in confinement1 were with the doubtful exception of one or two of the smallest grains1 not at all rounded4 ,nevertheless some of them appeared a little worn1 though not rounded4 ,notwithstanding these cases1 if we consider the evidence above given1 there can be little doubt that the fragments1 which serve as millstones in the gizzards of worms1 suffer1 when of a not very hard texture1 some amount of attrition2 and that the smaller particles in the earth1 which is habitually swallowed in such astonishingly large quantities by worms1 are ground together and are thus levigated4 ,if this be the case1 the 8terra tenuissima10--the 8pte excessivement fine10--of which the castings largely consist1 is in part due to the mechanical action of the gizzard2 #bcd and this fine matter1 as we shall see in the next chapter1 is that which is chiefly washed away from the innumerable castings on every field during each heavy shower of rain4 ,if the softer stones yield at all1 the harder ones will suffer some slight amount of wear and tear4 ,the trituration of small particles of stone in the gizzards of worms is of more importance under a geological point of view than may at first appear to be the case2 for ,mr4 ,sorby has clearly shown that the ordinary means of disintegration1 namely1 running water and the waves of the sea1 act with less and less power on fragments of rock the smaller they are4 8,hence10 as he remarks1 8even making no allowance for the extra buoying up of very minute particles by a current of water1 depending on surface cohesion1 the effects of wearing on the form of the grains must vary directly as their diameter or thereabouts4 ,if so1 a grain of #a_/aj an inch in diameter would be worn ten times as much as one of an inch in diameter1 and at least a hundred times as much as one of #a_/ajj an inch in diameter4 ,perhaps1 then1 we may conclude that a grain #a_/aj of an inch in diameter would be worn as much or more in drifting a mile as a grain #a_/ajjj of an inch in being drifted #ajj miles4 ,on the same principle a pebble one inch in diameter would be worn relatively more by being drifted only a few hundred yards40 #bcf ,nor should we forget1 in considering the power which worms exert in triturating particles of rock1 that there is good evidence that on each acre of land1 which is sufficiently damp and not too sandy1 gravelly or rocky for worms to inhabit1 a weight of more than ten tons of earth annually passes through their bodies and is brought to the surface4 ,the result for a country of the size of ,great ,britain1 within a period not very long in a geological sense1 such as a million years1 cannot be insignificant2 for the ten tons of earth has to be multiplied first by the above number of years1 and then by the number of acres fully stocked with worms2 and in ,england1 together with ,scotland1 the land which is cultivated and is well fitted for these animals1 has been estimated at above #cb million acres4 ,the product is #cbj million million tons of earth4 ,,chapter ,,vi4 ,,the ,,denudation ,,of ,,the ,,land--continued4 ,denudation aided by recently ejected castings flowing down inclined grass-covered surfaces--,the amount of earth which annually flows downwards--,the effect of tropical rain on worm castings--,the finest particles of earth washed completely away from castings--,the disintegration of dried castings into pellets1 and their rolling down inclined surfaces--,the formation of little ledges on hill-sides1 in part due to the accumulation of disintegrated castings--,castings blown to leeward over level land--,an attempt to estimate the amount thus blown--,the degradation of ancient encampments and tumuli--,the preservation of the crowns and furrows on land anciently ploughed--,the formation and amount of mould over the ,chalk formation4 ,,we are now prepared to consider the more direct part which worms take in the denudation of the land4 ,when reflecting on sub-aerial denudation1 it formerly appeared to me1 as it has to others1 that a nearly level or very gently inclined surface1 covered with turf1 could suffer no loss during even a long lapse of time4 ,it may1 however1 be urged that at long intervals1 debacles of rain or water-spouts would remove all the mould from a very gentle slope2 but when examining the steep1 turf-covered slopes in ,glen ,roy1 ,i was struck with the fact how rarely any such event could have happened since the ,glacial period1 as was plain from the well-preserved state of the three successive 8roads0 or lake-margins4 ,but the difficulty in believing that earth in any appreciable quantity can be removed from a gently inclined surface1 covered with vegetation and matted with roots1 is removed through the agency of worms4 ,for the many castings which are thrown up during rain1 and those thrown up some little time before heavy rain1 flow for a short distance down an inclined surface4 ,moreover much of the finest levigated earth is washed completely away from the castings4 ,during dry weather castings often disintegrate into small rounded pellets1 and these from their weight often roll down any slope4 ,this is more especially apt to occur when they are started by the wind1 and probably when started by the touch of an animal1 however small4 ,we shall also see that a strong wind blows all the castings1 even on a level field1 to leeward1 whilst they are soft2 and in like manner the pellets when they are dry4 ,if the wind blows in nearly the direction of an inclined surface1 the flowing down of the castings is much aided4 ,the observations on which these several statements are founded must now be given in some detail4 ,castings when first ejected are viscid and soft2 during rain1 at which time worms apparently prefer to eject them1 they are still softer2 so that ,i have sometimes thought that worms must swallow much water at such times4 ,however this may be1 rain1 even when not very heavy1 if long continued1 renders recently-ejected castings semi-fluid2 and on level ground they then spread out into thin1 circular1 flat discs1 exactly as would so much honey or very soft mortar1 with all traces of their vermiform structure lost4 ,this latter fact was sometimes made evident1 when a worm had subsequently bored through a flat circular disc of this kind1 and heaped up a fresh vermiform mass in the centre4 ,these flat subsided discs have been repeatedly seen by me after heavy rain1 in many places on land of all kinds4 ,on the flowing of wet castings1 and the rolling of dry disintegrated castings down inclined surfaces4--,when castings are ejected on an inclined surface during or shortly before heavy rain1 they cannot fail to flow a little down the slope4 ,thus1 on some steep slopes in ,knole ,park1 which were covered with coarse grass and had apparently existed in this state from time immemorial1 ,i found 7,oct4 #bb1 #ahgb7 after several wet days that almost all the many castings were considerably elongated in the line of the slope2 and that they now consisted of smooth1 only slightly conical masses4 ,whenever the mouths of the burrows could be found from which the earth had been ejected1 there was more earth below than above them4 ,after some heavy storms of rain 7,jan4 #be1 #ahgb7 two rather steeply inclined fields near ,down1 which had formerly been ploughed and were now rather sparsely clothed with poor grass1 were visited1 and many castings extended down the slopes for a length of #e inches1 which was twice or thrice the usual diameter of the castings thrown up on the level parts of these same fields4 ,on some fine grassy slopes in ,holwood ,park1 inclined at angles between #h and #aa #cj with the horizon1 where the surface apparently had never been disturbed by the hand of man1 castings abounded in extraordinary numbers3 and a space #af inches in length transversely to the slope and #f inches in the line of the slope1 was completely coated1 between the blades of grass1 with a uniform sheet of confluent and subsided castings4 ,here also in many places the castings had flowed down the slope1 and now formed smooth narrow patches of earth1 #f1 #g1 and #g inches in length4 ,some of these consisted of two castings1 one above the other1 which had become so completely confluent that they could hardly be distinguished4 ,on my lawn1 clothed with very fine grass1 most of the castings are black1 but some are yellowish from earth having been brought up from a greater depth than usual1 and the flowing-down of these yellow castings after heavy rain1 could be clearly seen where the slope was #e2 and where it was less than #a some evidence of their flowing down could still be detected4 ,on another occasion1 after rain which was never heavy1 but which lasted for #ah hours1 all the castings on this same gently inclined lawn had lost their vermiform structure2 and they had flowed1 so that fully two-thirds of the ejected earth lay below the mouths of the burrows4 ,these observations led me to make others with more care4 ,eight castings were found on my lawn1 where the grass-blades are fine and close together1 and three others on a field with coarse grass4 ,the inclination of the surface at the eleven places where these castings were collected varied between #d #cj and #ag #cj2 the mean of the eleven inclinations being #i #bf4 ,the length of the castings in the direction of the slope was first measured with as much accuracy as their irregularities would permit4 ,it was found possible to make these measurements within about of an inch1 but one of the castings was too irregular to admit of measurement4 ,the average length in the direction of the slope of the remaining ten castings was #b4jc inches4 ,the castings were then divided with a knife into two parts along a horizontal line passing through the mouth of the burrow1 which was discovered by slicing off the turf2 and all the ejected earth was separately collected1 namely1 the part above the hole and the part below4 ,afterwards these two parts were weighed4 ,in every case there was much more earth below than above2 the mean weight of that above being #ajc grains1 and of that below #bje grains2 so that the latter was very nearly double the former4 ,as on level ground castings are commonly thrown up almost equally round the mouths of the burrows1 this difference in weight indicates the amount of ejected earth which had flowed down the slope4 ,but very many more observations would be requisite to arrive at any general result2 for the nature of the vegetation and other accidental circumstances1 such as the heaviness of the rain1 the direction and force of the wind1 c41 appear to be more important in determining the quantity of the earth which flows down a slope than its angle4 ,thus with four castings on my lawn 7included in the above eleven7 where the mean slope was #g #ai1 the difference in the amount of earth above and below the burrows was greater than with three other castings on the same lawn where the mean slope was #ab #e4 ,we may1 however1 take the above eleven cases1 which are accurate as far as they go1 and calculate the weight of the ejected earth which annually flows down a slope having a mean inclination of #i #bf4 ,this was done by my son ,george4 ,it has been shown that almost exactly two-thirds of the ejected earth is found below the mouth of the burrow and one-third above it4 ,now if the two-thirds which is below the hole be divided into two equal parts1 the upper half of this two-thirds exactly counterbalances the one-third which is above the hole1 so that as far as regards the one-third above and the upper half of the two-thirds below1 there is no flow of earth down the hill-side4 ,the earth constituting the lower half of the two-thirds is1 however1 displaced through distances which are different for every part of it1 but which may be represented by the distance between the middle point of the lower half of the two-thirds and the hole4 ,so that the average distance of displacement is a half of the whole length of the worm-casting4 ,now the average length of ten out of the above eleven castings was #b4jc inches1 and half of this we may take as being #a inch4 ,it may therefore be concluded that one-third of the whole earth brought to the surface was in these cases carried down the slope through #a inch4 #bdd ,it was shown in the third chapter that on ,leith ,hill ,common1 dry earth weighing at least #g4dec lbs4 was brought up by worms to the surface on a square yard in the course of a year4 ,if a square yard be drawn on a hillside with two of its sides horizontal1 then it is clear that only #a_/cf part of the earth brought up on that square yard would be near enough to its lower side to cross it1 supposing the displacement of the earth to be through one inch4 ,but it appears that only of the earth brought up can be considered to flow downwards2 hence of #a_/cf or #a_/ajh of #g4dec lbs4 will cross the lower side of our square yard in a year4 ,now #a_/ajh of #g4dec lbs4 is #a4a oz4 ,therefore #a4a oz4 of dry earth will annually cross each linear yard running horizontally along a slope having the above inclination2 or very nearly #g lbs4 will annually cross a horizontal line1 #ajj yards in length1 on a hill-side having this inclination4 ,a more accurate1 though still very rough1 calculation can be made of the bulk of earth1 which in its natural damp state annually flows down the same slope over a yard-line drawn horizontally across it4 ,from the several cases given in the third chapter1 it is known that the castings annually brought to the surface on a square yard1 if uniformly spread out would form a layer #j4b of an inch in thickness3 it therefore follows by a calculation similar to the one already given1 that of #j4b #cf1 or #b4d cubic inches of damp earth will annually cross a horizontal line one yard in length on a hillside with the above inclination4 ,this bulk of damp castings was found to weigh #a4he oz4 ,therefore #aa4ef lbs4 of damp earth1 instead of #g lbs4 of dry earth as by the former calculation1 would annually cross a line #ajj yards in length on our inclined surface4 ,in these calculations it has been assumed that the castings flow a short distance downwards during the whole year1 but this occurs only with those ejected during or shortly before rain2 so that the above results are thus far exaggerated4 ,on the other hand1 during rain much of the finest earth is washed to a considerable distance from the castings1 even where the slope is an extremely gentle one1 and is thus wholly lost as far as the above calculations are concerned4 ,castings ejected during dry weather and which have set hard1 lose in the same manner a considerable quantity of fine earth4 ,dried castings1 moreover1 are apt to disintegrate into little pellets1 which often roll or are blown down any inclined surface4 ,therefore the above result1 namely1 that #bd cubic inches of earth 7weighing #a4he oz4 whilst damp7 annually crosses a yard-line of the specified kind1 is probably not much if at all exaggerated4 ,this amount is small2 but we should bear in mind how many branching valleys intersect most countries1 the whole length of which must be very great2 and that earth is steadily travelling down both turf-covered sides of each valley4 ,for every #ajj yards in length in a valley with sides sloping as in the foregoing cases1 #dhj cubic inches of damp earth1 weighing above #bc pounds1 will annually reach the bottom4 ,here a thick bed of alluvium will accumulate1 ready to be washed away in the course of centuries1 as the stream in the middle meanders from side to side4 ,if it could be shown that worms generally excavate their burrows at right angles to an inclined surface1 and this would be their shortest course for bringing up earth from beneath1 then as the old burrows collapsed from the weight of the superincumbent soil1 the collapsing would inevitably cause the whole bed of vegetable mould to sink or slide slowly down the inclined surface4 ,but to ascertain the direction of many burrows was found too difficult and troublesome4 ,a straight piece of wire was1 however1 pushed into twenty-five burrows on several sloping fields1 and in eight cases the burrows were nearly at right angles to the slope2 whilst in the remaining cases they were indifferently directed at various angles1 either upwards or downwards with respect to the slope4 ,in countries where the rain is very heavy1 as in the tropics1 the castings appear1 as might have been expected1 to be washed down in a greater degree than in ,england4 ,mr4 ,scott informs me that near ,calcutta the tall columnar castings 7previously described71 the diameter of which is usually between #a and #a inch1 subside on a level surface1 after heavy rain1 into almost circular1 thin1 flat discs1 between #c and #d and sometimes #e inches in diameter4 ,three fresh castings1 which had been ejected in the ,botanic ,gardens 8on a slightly inclined1 grass-covered1 artificial bank of loamy clay10 were carefully measured1 and had a mean height of #b4ag1 and a mean diameter of #a4dc inches2 these after heavy rain1 formed elongated patches of earth1 with a mean length in the direction of the slope of #e4hc inches4 ,as the earth had spread very little up the slope1 a large part1 judging from the original diameter of these castings1 must have flowed bodily downwards about #d inches4 ,moreover some of the finest earth of which they were composed must have been washed completely away to a still greater distance4 ,in drier sites near ,calcutta1 a species of worm ejects its castings1 not in vermiform masses1 but in little pellets of varying sizes3 these are very numerous in some places1 and ,mr4 ,scott says that they 8are washed away by every shower40 ,i was led to believe that a considerable quantity of fine earth is washed quite away from castings during rain1 from the surfaces of old ones being often studded with coarse particles4 ,accordingly a little fine precipitated chalk1 moistened with saliva or gum-water1 so as to be slightly viscid and of the same consistence as a fresh casting1 was placed on the summits of several castings and gently mixed with them4 ,these castings were then watered through a very fine rose1 the drops from which were closer together than those of rain1 but not nearly so large as those in a thunderstorm2 nor did they strike the ground with nearly so much force as drops during heavy rain4 ,a casting thus treated subsided with surprising slowness1 owing as ,i suppose to its viscidity4 ,it did not flow bodily down the grass-covered surface of the lawn1 which was here inclined at an angle of #af #bj2 nevertheless many particles of the chalk were found three inches below the casting4 ,the experiment was repeated on three other castings on different parts of the lawn1 which sloped at #b #cj1 #c and #f2 and particles of chalk could be seen between #d and #e inches below the casting2 and after the surface had become dry1 particles were found in two cases at a distance of #e and #f inches4 ,several other castings with precipitated chalk placed on their summits were left to the natural action of the rain4 ,in one case1 after rain which was not heavy1 the casting was longitudinally streaked with white4 ,in two other cases the surface of the ground was rendered somewhat white for a distance of one inch from the casting2 and some soil collected at a distance of #b inches1 where the slope was #g1 effervesced slightly when placed in acid4 ,after one or two weeks1 the chalk was wholly or almost wholly washed away from all the castings on which it had been placed1 and these had recovered their natural colour4 ,it may be here remarked that after very heavy rain shallow pools may be seen on level or nearly level fields1 where the soil is not very porous1 and the water in them is often slightly muddy2 when such little pools have dried1 the leaves and blades of grass at their bottoms are generally coated with a thin layer of mud4 ,this mud ,i believe is derived in large part from recently ejected castings4 ,dr4 ,king informs me that the majority of the before described gigantic castings1 which he found on a fully exposed1 bare1 gravelly knoll on the ,nilgiri ,mountains in ,india1 had been more or less weathered by the previous north-east monsoon2 and most of them presented a subsided appearance4 ,the worms here eject their castings only during the rainy season2 and at the time of ,dr4 ,king's visit no rain had fallen for #aaj days4 ,he carefully examined the ground between the place where these huge castings lay1 and a little watercourse at the base of the knoll1 and nowhere was there any accumulation of fine earth1 such as would necessarily have been left by the disintegration of the castings if they had not been wholly removed4 ,he therefore has no hesitation in asserting that the whole of these huge castings are annually washed during the two monsoons 7when about #ajj inches of rain fall7 into the little water-course1 and thence into the plains lying below at a depth of #cjjj or #djjj feet4 ,castings ejected before or during dry weather become hard1 sometimes surprisingly hard1 from the particles of earth having been cemented together by the intestinal secretions4 ,frost seems to be less effective in their disintegration than might have been expected4 ,nevertheless they readily disintegrate into small pellets1 after being alternately moistened with rain and again dried4 ,those which have flowed during rain down a slope1 disintegrate in the same manner4 ,such pellets often roll a little down any sloping surface2 their descent being sometimes much aided by the wind4 ,the whole bottom of a broad dry ditch in my grounds1 where there were very few fresh castings1 was completely covered with these pellets or disintegrated castings1 which had rolled down the steep sides1 inclined at an angle of #bg4 ,near ,nice1 in places where the great cylindrical castings1 previously described1 abound1 the soil consists of very fine arenaceo-calcareous loam2 and ,dr4 ,king informs me that these castings are extremely liable to crumble during dry weather into small fragments1 which are soon acted on by rain1 and then sink down so as to be no longer distinguishable from the surrounding soil4 ,he sent me a mass of such disintegrated castings1 collected on the top of a bank1 where none could have rolled down from above4 ,they must have been ejected within the previous five or six months1 but they now consisted of more or less rounded fragments of all sizes1 from of an inch in diameter to minute grains and mere dust4 ,dr4 ,king witnessed the crumbling process whilst drying some perfect castings1 which he afterwards sent me4 ,mr4 ,scott also remarks on the crumbling of the castings near ,calcutta and on the mountains of ,sikkim during the hot and dry season4 ,when the castings near ,nice had been ejected on an inclined surface1 the disintegrated fragments rolled downwards1 without losing their distinctive shape2 and in some places could 8be collected in basketfuls40 ,dr4 ,king observed a striking instance of this fact on the ,corniche road1 where a drain1 about #b feet wide and #i inches deep1 had been made to catch the surface drainage from the adjoining hill-side4 ,the bottom of this drain was covered for a distance of several hundred yards1 to a depth of from #a to #c inches1 by a layer of broken castings1 still retaining their characteristic shape4 ,nearly all these innumerable fragments had rolled down from above1 for extremely few castings had been ejected in the drain itself4 ,the hill-side was steep1 but varied much in inclination1 which ,dr4 ,king estimated at from #cj to #fj with the horizon4 ,he climbed up the slope1 and 8found every here and there little embankments1 formed by fragments of the castings that had been arrested in their downward progress by irregularities of the surface1 by stones1 twigs1 c4 ,one little group of plants of ,anemone hortensis had acted in this manner1 and quite a small bank of soil had collected round it4 ,much of this soil had crumbled down1 but a great deal of it still retained the form of castings40 ,dr4 ,king dug up this plant1 and was struck with the thickness of the soil which must have recently accumulated over the crown of the rhizoma1 as shown by the length of the bleached petioles1 in comparison with those of other plants of the same kind1 where there had been no such accumulation4 ,the earth thus accumulated had no doubt been secured 7as ,i have everywhere seen7 by the smaller roots of the plants4 ,after describing this and other analogous cases1 ,dr4 ,king concludes3 8,i can have no doubt that worms help greatly in the process of denudation40 ,ledges of earth on steep hill-sides4--,little horizontal ledges1 one above another1 have been observed on steep grassy slopes in many parts of the world4 ,the formation has been attributed to animals travelling repeatedly along the slope in the same horizontal lines while grazing1 and that they do thus move and use the ledges is certain2 but ,professor ,henslow 7a most careful observer7 told ,sir ,j4 ,hooker that he was convinced that this was not the sole cause of their formation4 ,sir ,j4 ,hooker saw such ledges on the ,himalayan and ,atlas ranges1 where there were no domesticated animals and not many wild ones2 but these latter would1 it is probable1 use the ledges at night while grazing like our domesticated animals4 ,a friend observed for me the ledges on the ,alps of ,switzerland1 and states that they ran at #c or #d ft4 one above the other1 and were about a foot in breadth4 ,they had been deeply pitted by the feet of grazing cows4 ,similar ledges were observed by the same friend on our ,chalk downs1 and on an old talus of chalk-fragments 7thrown out of a quarry7 which had become clothed with turf4 ,my son ,francis examined a ,chalk escarpment near ,lewes2 and here on a part which was very steep1 sloping at #dj with the horizon1 about #cj flat ledges extended horizontally for more than #ajj yards1 at an average distance of about #bj inches1 one beneath the other4 ,they were from #i to #aj inches in breadth4 ,when viewed from a distance they presented a striking appearance1 owing to their parallelism2 but when examined closely1 they were seen to be somewhat sinuous1 and one often ran into another1 giving the appearance of the ledge having forked into two4 ,they are formed of light-coloured earth1 which on the outside1 where thickest1 was in one case #i inches1 and in another case between #f and #g inches in thickness4 ,above the ledges1 the thickness of the earth over the chalk was in the former case #d and in the latter only #c inches4 ,the grass grew more vigorously on the outer edges of the ledges than on any other part of the slope1 and here formed a tufted fringe4 ,their middle part was bare1 but whether this had been caused by the trampling of sheep1 which sometimes frequent the ledges1 my son could not ascertain4 ,nor could he feel sure how much of the earth on the middle and bare parts1 consisted of disintegrated worm-castings which had rolled down from above2 but he felt convinced that some had thus originated2 and it was manifest that the ledges with their grass-fringed edges would arrest any small object rolling down from above4 ,at one end or side of the bank bearing these ledges1 the surface consisted in parts of bare chalk1 and here the ledges were very irregular4 ,at the other end of the bank1 the slope suddenly became less steep1 and here the ledges ceased rather abruptly2 but little embankments only a foot or two in length were still present4 ,the slope became steeper lower down the hill1 and the regular ledges then reappeared4 ,another of my sons observed1 on the inland side of ,beachy ,head1 where the surface sloped at about #be1 many short little embankments like those just mentioned4 ,they extended horizontally and were from a few inches to two or three feet in length4 ,they supported tufts of grass growing vigorously4 ,the average thickness of the mould of which they were formed1 taken from nine measurements1 was #d4e inches2 while that of the mould above and beneath them was on an average only #c4b inches1 and on each side1 on the same level1 #c4a inches4 ,on the upper parts of the slope1 these embankments showed no signs of having been trampled on by sheep1 but in the lower parts such signs were fairly plain4 ,no long continuous ledges had here been formed4 ,if the little embankments above the ,corniche road1 which ,dr4 ,king saw in the act of formation by the accumulation of disintegrated and rolled worm-castings1 were to become confluent along horizontal lines1 ledges would be formed4 ,each embankment would tend to extend laterally by the lateral extension of the arrested castings2 and animals grazing on a steep slope would almost certainly make use of every prominence at nearly the same level1 and would indent the turf between them2 and such intermediate indentations would again arrest the castings4 ,an irregular ledge when once formed would also tend to become more regular and horizontal by some of the castings rolling laterally from the higher to the lower parts1 which would thus be raised4 ,any projection beneath a ledge would not afterwards receive disintegrated matter from above1 and would tend to be obliterated by rain and other atmospheric agencies4 ,there is some analogy between the formation1 as here supposed1 of these ledges1 and that of the ripples of wind-drifted sand as described by ,lyell4 #bei ,the steep1 grass-covered sides of a mountainous valley in ,westmoreland1 called ,grisedale1 was marked in many places with innumerable lines of miniature cliffs1 with almost horizontal1 little ledges at their bases4 ,their formation was in no way connected with the action of worms1 for castings could not anywhere be seen 7and their absence is an inexplicable fact71 although the turf lay in many places over a considerable thickness of boulder-clay and moraine rubbish4 ,nor1 as far as ,i could judge1 was the formation of these little cliffs at all closely connected with the trampling of cows or sheep4 ,it appeared as if the whole superficial1 somewhat argillaceous earth1 while partially held together by the roots of the grasses1 had slided a little way down the mountain sides2 and in thus sliding1 had yielded and cracked in horizontal lines1 transversely to the slope4 ,castings blown to leeward by the wind4--,we have seen that moist castings flow1 and that disintegrated castings roll down any inclined surface2 and we shall now see that castings1 recently ejected on level grass-covered surfaces1 are blown during gales of wind accompanied by rain to leeward4 ,this has been observed by me many times on many fields during several successive years4 ,after such gales1 the castings present a gently inclined and smooth1 or sometimes furrowed1 surface to windward1 while they are steeply inclined or precipitous to leeward1 so that they resemble on a miniature scale glacier-ground hillocks of rock4 ,they are often cavernous on the leeward side1 from the upper part having curled over the lower part4 ,during one unusually heavy south-west gale with torrents of rain1 many castings were wholly blown to leeward1 so that the mouths of the burrows were left naked and exposed on the windward side4 ,recent castings naturally flow down an inclined surface1 but on a grassy field1 which sloped between #aj and #ae1 several were found after a heavy gale blown up the slope4 ,this likewise occurred on another occasion on a part of my lawn where the slope was somewhat less4 ,on a third occasion1 the castings on the steep1 grass-covered sides of a valley1 down which a gale had blown1 were directed obliquely instead of straight down the slope2 and this was obviously due to the combined action of the wind and gravity4 ,four castings on my lawn1 where the downward inclination was #j #de1 #a1 #c and #c #cj 7mean #b #de7 towards the north-east1 after a heavy south-west gale with rain1 were divided across the mouths of the burrows and weighed in the manner formerly described4 ,the mean weight of the earth below the mouths of burrows and to leeward1 was to that above the mouths and on the windward side as #b to #a2 whereas we have seen that with several castings which had flowed down slopes having a mean inclination of #i #bf1 and with three castings where the inclination was above #ab2 the proportional weight of the earth below to that above the burrows was as only #b to #a4 ,these several cases show how efficiently gales of wind accompanied by rain act in displacing recently ejected castings4 ,we may therefore conclude that even a moderately strong wind will produce some slight effect on them4 ,dry and indurated castings1 after their disintegration into small fragments or pellets1 are sometimes1 probably often1 blown by a strong wind to leeward4 ,this was observed on four occasions1 but ,i did not sufficiently attend to this point4 ,one old casting on a gently sloping bank was blown quite away by a strong south-west wind4 ,dr4 ,king believes that the wind removes the greater part of the old crumbling castings near ,nice4 ,several old castings on my lawn were marked with pins and protected from any disturbance4 ,they were examined after an interval of #aj weeks1 during which time the weather had been alternately dry and rainy4 ,some1 which were of a yellowish colour had been washed almost completely away1 as could be seen by the colour of the surrounding ground4 ,others had completely disappeared1 and these no doubt had been blown away4 ,lastly1 others still remained and would long remain1 as blades of grass had grown through them4 ,on poor pasture-land1 which has never been rolled and has not been much trampled on by animals1 the whole surface is sometimes dotted with little pimples1 through and on which grass grows2 and these pimples consist of old worm-castings4 ,in all the many observed cases of soft castings blown to leeward1 this had been effected by strong winds accompanied by rain4 ,as such winds in ,england generally blow from the south and south-west1 earth must on the whole tend to travel over our fields in a north and north-east direction4 ,this fact is interesting1 because it might be thought that none could be removed from a level1 grass-covered surface by any means4 ,in thick and level woods1 protected from the wind1 castings will never be removed as long as the wood lasts2 and mould will here tend to accumulate to the depth at which worms can work4 ,i tried to procure evidence as to how much mould is blown1 whilst in the state of castings1 by our wet southern gales to the north-east1 over open and flat land1 by looking to the level of the surface on opposite sides of old trees and hedge-rows2 but ,i failed owing to the unequal growth of the roots of trees and to most pasture-land having been formerly ploughed4 ,on an open plain near ,stonehenge1 there exist shallow circular trenches1 with a low embankment outside1 surrounding level spaces #ej yards in diameter4 ,these rings appear very ancient1 and are believed to be contemporaneous with the ,druidical stones4 ,castings ejected within these circular spaces1 if blown to the north-east by south-west winds would form a layer of mould within the trench1 thicker on the north-eastern than on any other side4 ,but the site was not favourable for the action of worms1 for the mould over the surrounding ,chalk formation with flints1 was only #c4cg inches in thickness1 from a mean of six observations made at a distance of #aj yards outside the embankment4 ,the thickness of the mould within two of the circular trenches was measured every #e yards all round1 on the inner sides near the bottom4 ,my son ,horace protracted these measurements on paper2 and though the curved line representing the thickness of the mould was extremely irregular1 yet in both diagrams it could be seen to be thicker on the north-eastern side than elsewhere4 ,when a mean of all the measurements in both the trenches was laid down and the line smoothed1 it was obvious that the mould was thickest in the quarter of the circle between north-west and north-east2 and thinnest in the quarter between south-east and south-west1 especially at this latter point4 ,besides the foregoing measurements1 six others were taken near together in one of the circular trenches1 on the north-east side2 and the mould here had a mean thickness of #b4bi inches2 while the mean of six other measurements on the south-west side was only #a4df inches4 ,these observations indicate that the castings had been blown by the south-west winds from the circular enclosed space into the trench on the north-east side2 but many more measurements in other analogous cases would be requisite for a trustworthy result4 ,the amount of fine earth brought to the surface under the form of castings1 and afterwards transported by the winds accompanied by rain1 or that which flows and rolls down an inclined surface1 no doubt is small in the course of a few scores of years2 for otherwise all the inequalities in our pasture fields would be smoothed within a much shorter period than appears to be the case4 ,but the amount which is thus transported in the course of thousands of years cannot fail to be considerable and deserves attention4 4 de ,beaumont looks at the vegetable mould which everywhere covers the land as a fixed line1 from which the amount of denudation may be measured4 #bfe ,he ignores the continued formation of fresh mould by the disintegration of the underlying rocks and fragments of rock2 and it is curious to find how much more philosophical were the views maintained long ago1 by ,playfair1 who1 in #ahjb1 wrote1 8,in the permanence of a coat of vegetable mould on the surface of the earth1 we have a demonstrative proof of the continued destruction of the rocks40 #bff ,ancient encampments and tumuli4--4 de ,beaumont adduces the present state of many ancient encampments and tumuli and of old ploughed fields1 as evidence that the surface of the land undergoes hardly any degradation4 ,but it does not appear that he ever examined the thickness of the mould over different parts of such old remains4 ,he relies chiefly on indirect1 but apparently trustworthy1 evidence that the slopes of the old embankments are the same as they originally were2 and it is obvious that he could know nothing about their original heights4 ,in ,knole ,park a mound had been thrown up behind the rifle-targets1 which appeared to have been formed of earth originally supported by square blocks of turf4 ,the sides sloped1 as nearly as ,i could estimate them1 at an angle of #de or #ej with the horizon1 and they were covered1 especially on the northern side1 with long coarse grass1 beneath which many worm-castings were found4 ,these had flowed bodily downwards1 and others had rolled down as pellets4 ,hence it is certain that as long as a mound of this kind is tenanted by worms1 its height will be continually lowered4 ,the fine earth which flows or rolls down the sides of such a mound accumulates at its base in the form of a talus4 ,a bed1 even a very thin bed1 of fine earth is eminently favourable for worms2 so that a greater number of castings would tend to be ejected on a talus thus formed than elsewhere2 and these would be partially washed away by every heavy shower and be spread over the adjoining level ground4 ,the final result would be the lowering of the whole mound1 whilst the inclination of the sides would not be greatly lessened4 ,the same result would assuredly follow with ancient embankments and tumuli2 except where they had been formed of gravel or of nearly pure sand1 as such matter is unfavourable for worms4 ,many old fortifications and tumuli are believed to be at least #bjjj years old2 and we should bear in mind that in many places about one inch of mould is brought to the surface in #e years or two inches in #aj years4 ,therefore in so long a period as #bjjj years1 a large amount of earth will have been repeatedly brought to the surface on most old embankments and tumuli1 especially on the talus round their bases1 and much of this earth will have been washed completely away4 ,we may therefore conclude that all ancient mounds1 when not formed of materials unfavourable to worms1 will have been somewhat lowered in the course of centuries1 although their inclinations may not have been greatly changed4 ,fields formerly ploughed4--,from a very remote period and in many countries1 land has been ploughed1 so that convex beds1 called crowns or ridges1 usually about #h feet across and separated by furrows1 have been thrown up4 ,the furrows are directed so as to carry off the surface water4 ,in my attempts to ascertain how long a time these crowns and furrows last1 when ploughed land has been converted into pasture1 obstacles of many kinds were encountered4 ,it is rarely known when a field was last ploughed2 and some fields which were thought to have been in pasture from time immemorial were afterwards discovered to have been ploughed only #ej or #fj years before4 ,during the early part of the present century1 when the price of corn was very high1 land of all kinds seems to have been ploughed in ,britain4 ,there is1 however1 no reason to doubt that in many cases the old crowns and furrows have been preserved from a very ancient period4 #bfi ,that they should have been preserved for very unequal lengths of time would naturally follow from the crowns1 when first thrown up1 having differed much in height in different districts1 as is now the case with recently ploughed land4 ,in old pasture fields1 the mould1 wherever measurements were made1 was found to be from to #b inches thicker in the furrows than on the crowns2 but this would naturally follow from the finer earth having been washed from the crowns into the furrows before the land was well clothed with turf2 and it is impossible to tell what part worms may have played in the work4 ,nevertheless from what we have seen1 castings would certainly tend to flow and to be washed during heavy rain from the crowns into the furrows4 ,but as soon as a bed of fine earth had by any means been accumulated in the furrows1 it would be more favourable for worms than the other parts1 and a greater number of castings would be thrown up here than elsewhere2 and as the furrows on sloping land are usually directed so as to carry off the surface water1 some of the finest earth would be washed from the castings which had been here ejected and be carried completely away4 ,the result would be that the furrows would be filled up very slowly1 while the crowns would be lowered perhaps still more slowly by the flowing and rolling of the castings down their gentle inclinations into the furrows4 ,nevertheless it might be expected that old furrows1 especially those on a sloping surface1 would in the course of time be filled up and disappear4 ,some careful observers1 however1 who examined fields for me in ,gloucestershire and ,staffordshire could not detect any difference in the state of the furrows in the upper and lower parts of sloping fields1 supposed to have been long in pasture2 and they came to the conclusion that the crowns and furrows would last for an almost endless number of centuries4 ,on the other hand the process of obliteration seems to have commenced in some places4 ,thus in a grass field in ,north ,wales1 known to have been ploughed about #fe years ago1 which sloped at an angle of #ae to the north-east1 the depth of the furrows 7only #g feet apart7 was carefully measured1 and was found to be about #d inches in the upper part of the slope1 and only #a inch near the base1 where they could be traced with difficulty4 ,on another field sloping at about the same angle to the south-west1 the furrows were scarcely perceptible in the lower part2 although these same furrows when followed on to some adjoining level ground were from #b to #c inches in depth4 ,a third and closely similar case was observed4 ,in a fourth case1 the mould in a furrow in the upper part of a sloping field was #b inches1 and in the lower part #d inches in thickness4 ,on the ,chalk ,downs at about a mile distance from ,stonehenge1 my son ,william examined a grass-covered1 furrowed surface1 sloping at from #h to #aj 1 which an old shepherd said had not been ploughed within the memory of man4 ,the depth of one furrow was measured at #af points in a length of #fh paces1 and was found to be deeper where the slope was greatest and where less earth would naturally tend to accumulate1 and at the base it almost disappeared4 ,the thickness of the mould in this furrow in the upper part was #b inches1 which increased to #e inches1 a little above the steepest part of the slope2 and at the base1 in the middle of the narrow valley1 at a point which the furrow if continued would have struck1 it amounted to #g inches4 ,on the opposite side of the valley1 there were very faint1 almost obliterated1 traces of furrows4 ,another analogous but not so decided a case was observed at a few miles' distance from ,stonehenge4 ,on the whole it appears that the crowns and furrows on land formerly ploughed1 but now covered with grass1 tend slowly to disappear when the surface is inclined2 and this is probably in large part due to the action of worms2 but that the crowns and furrows last for a very long time when the surface is nearly level4 ,formation and amount of mould over the ,chalk ,formation4--,worm-castings are often ejected in extraordinary numbers on steep1 grass-covered slopes1 where the ,chalk comes close to the surface1 as my son ,william observed near ,winchester and elsewhere4 ,if such castings are largely washed away during heavy rains1 it is difficult to understand at first how any mould can still remain on our ,downs1 as there does not appear any evident means for supplying the loss4 ,there is1 moreover1 another cause of loss1 namely1 in the percolation of the finer particles of earth into the fissures in the chalk and into the chalk itself4 ,these considerations led me to doubt for a time whether ,i had not exaggerated the amount of fine earth which flows or rolls down grass-covered slopes under the form of castings2 and ,i sought for additional information4 ,in some places1 the castings on ,chalk ,downs consist largely of calcareous matter1 and here the supply is of course unlimited4 ,but in other places1 for instance on a part of ,teg ,down near ,winchester1 the castings were all black and did not effervesce with acids4 ,the mould over the chalk was here only from #c to #d inches in thickness4 ,so again on the plain near ,stonehenge1 the mould1 apparently free from calcareous matter1 averaged rather less than #c inches in thickness4 ,why worms should penetrate and bring up chalk in some places and not in others ,i do not know4 ,in many districts where the land is nearly level1 a bed several feet in thickness of red clay full of unworn flints overlies the ,upper ,chalk4 ,this overlying matter1 the surface of which has been converted into mould1 consists of the undissolved residue from the chalk4 ,it may be well here to recall the case of the fragments of chalk buried beneath worm-castings on one of my fields1 the angles of which were so completely rounded in the course of #bi years that the fragments now resembled water-worn pebbles4 ,this must have been effected by the carbonic acid in the rain and in the ground1 by the humus-acids1 and by the corroding power of living roots4 ,why a thick mass of residue has not been left on the ,chalk1 wherever the land is nearly level1 may perhaps be accounted for by the percolation of the fine particles into the fissures1 which are often present in the chalk and are either open or are filled up with impure chalk1 or into the solid chalk itself4 ,that such percolation occurs can hardly be doubted4 ,my son collected some powdered and fragmentary chalk beneath the turf near ,winchester2 the former was found by ,colonel ,parsons1 ,r4 ,e41 to contain #aj per cent41 and the fragments #h per cent4 of earthy matter4 ,on the flanks of the escarpment near ,abinger in ,surrey1 some chalk close beneath a layer of flints1 #b inches in thickness and covered by #h inches of mould1 yielded a residue of #c4g per cent4 of earthy matter4 ,on the other hand the ,upper ,chalk properly contains1 as ,i was informed by the late ,david ,forbes who had made many analyses1 only from #a to #b per cent4 of earthy matter2 and two samples from pits near my house contained #a4c and #j4f per cent4 ,i mention these latter cases because1 from the thickness of the overlying bed of red clay with flints1 ,i had imagined that the underlying chalk might here be less pure than elsewhere4 ,the cause of the residue accumulating more in some places than in others1 may be attributed to a layer of argillaceous matter having been left at an early period on the chalk1 and this would check the subsequent percolation of earthy matter into it4 ,from the facts now given we may conclude that castings ejected on our ,chalk ,downs suffer some loss by the percolation of their finer matter into the chalk4 ,but such impure superficial chalk1 when dissolved1 would leave a larger supply of earthy matter to be added to the mould than in the case of pure chalk4 ,besides the loss caused by percolation1 some fine earth is certainly washed down the sloping grass-covered surfaces of our ,downs4 ,the washing-down process1 however1 will be checked in the course of time2 for although ,i do not know how thin a layer of mould suffices to support worms1 yet a limit must at last be reached2 and then their castings would cease to be ejected or would become scanty4 ,the following cases show that a considerable quantity of fine earth is washed down4 ,the thickness of the mould was measured at points #ab yards apart across a small valley in the ,chalk near ,winchester4 ,the sides sloped gently at first2 then became inclined at about #bj2 then more gently to near the bottom1 which transversely was almost level and about #ej yards across4 ,in the bottom1 the mean thickness of the mould from five measurements was #h4c inches2 whilst on the sides of the valley1 where the inclination varied between #ad and #bj1 its mean thickness was rather less than #c4e inches4 ,as the turf-covered bottom of the valley sloped at an angle of only between #b and #c1 it is probable that most of the #h4c-;inch layer of mould had been washed down from the flanks of the valley1 and not from the upper part4 ,but as a shepherd said that he had seen water flowing in this valley after the sudden thawing of snow1 it is possible that some earth may have been brought down from the upper part2 or1 on the other hand1 that some may have been carried further down the valley4 ,closely similar results1 with respect to the thickness of the mould1 were obtained in a neighbouring valley4 ,st4 ,catherine's ,hill1 near ,winchester1 is #cbg feet in height1 and consists of a steep cone of chalk about of a mile in diameter4 ,the upper part was converted by the ,romans1 or1 as some think1 by the ancient ,britons1 into an encampment1 by the excavation of a deep and broad ditch all round it4 ,most of the chalk removed during the work was thrown upwards1 by which a projecting bank was formed2 and this effectually prevents worm-castings 7which are numerous in parts71 stones1 and other objects from being washed or rolled into the ditch4 ,the mould on the upper and fortified part of the hill was found to be in most places only from #b to #c inches in thickness2 whereas it had accumulated at the foot of the embankment above the ditch to a thickness in most places of from #h to #i inches4 ,on the embankment itself the mould was only #a to #a inch in thickness2 and within the ditch at the bottom it varied from #b to #c1 but was in one spot #f inches in thickness4 ,on the north-west side of the hill1 either no embankment had ever been thrown up above the ditch1 or it had subsequently been removed2 so that here there was nothing to prevent worm-castings1 earth and stones being washed into the ditch1 at the bottom of which the mould formed a layer from #aa to #bb inches in thickness4 ,it should however be stated that here and on other parts of the slope1 the bed of mould often contained fragments of chalk and flint which had obviously rolled down at different times from above4 ,the interstices in the underlying fragmentary chalk were also filled up with mould4 ,my son examined the surface of this hill to its base in a south-west direction4 ,beneath the great ditch1 where the slope was about #bd1 the mould was very thin1 namely1 from #a to #b inches2 whilst near the base1 where the slope was only #c to #d1 it increased to between #h and #i inches in thickness4 ,we may therefore conclude that on this artificially modified hill1 as well as in the natural valleys of the neighbouring ,chalk ,downs1 some fine earth1 probably derived in large part from worm-castings1 is washed down1 and accumulates in the lower parts1 notwithstanding the percolation of an unknown quantity into the underlying chalk2 a supply of fresh earthy matter being afforded by the dissolution of the chalk through atmospheric and other agencies4 ,,chapter ,,vii4 ,,conclusion4 ,summary of the part which worms have played in the history of the world--,their aid in the disintegration of rocks--,in the denudation of the land--,in the preservation of ancient remains--,in the preparation of the soil for the growth of plants--,mental powers of worms--,conclusion4 ,,worms have played a more important part in the history of the world than most persons would at first suppose4 ,in almost all humid countries they are extraordinarily numerous1 and for their size possess great muscular power4 ,in many parts of ,england a weight of more than ten tons 7#aj1eaf kilogrammes7 of dry earth annually passes through their bodies and is brought to the surface on each acre of land2 so that the whole superficial bed of vegetable mould passes through their bodies in the course of every few years4 ,from the collapsing of the old burrows the mould is in constant though slow movement1 and the particles composing it are thus rubbed together4 ,by these means fresh surfaces are continually exposed to the action of the carbonic acid in the soil1 and of the humus-acids which appear to be still more efficient in the decomposition of rocks4 ,the generation of the humus-acids is probably hastened during the digestion of the many half-decayed leaves which worms consume4 ,thus the particles of earth1 forming the superficial mould1 are subjected to conditions eminently favourable for their decomposition and disintegration4 ,moreover1 the particles of the softer rocks suffer some amount of mechanical trituration in the muscular gizzards of worms1 in which small stones serve as mill-stones4 ,the finely levigated castings1 when brought to the surface in a moist condition1 flow during rainy weather down any moderate slope2 and the smaller particles are washed far down even a gently inclined surface4 ,castings when dry often crumble into small pellets and these are apt to roll down any sloping surface4 ,where the land is quite level and is covered with herbage1 and where the climate is humid so that much dust cannot be blown away1 it appears at first sight impossible that there should be any appreciable amount of sub-aerial denudation2 but worm-castings are blown1 especially whilst moist and viscid1 in one uniform direction by the prevalent winds which are accompanied by rain4 ,by these several means the superficial mould is prevented from accumulating to a great thickness2 and a thick bed of mould checks in many ways the disintegration of the underlying rocks and fragments of rock4 ,the removal of worm-castings by the above means leads to results which are far from insignificant4 ,it has been shown that a layer of earth1 #j4b of an inch in thickness1 is in many places annually brought to the surface2 and if a small part of this amount flows1 or rolls1 or is washed1 even for a short distance1 down every inclined surface1 or is repeatedly blown in one direction1 a great effect will be produced in the course of ages4 ,it was found by measurements and calculations that on a surface with a mean inclination of #i #bf1 #b4d cubic inches of earth which had been ejected by worms crossed1 in the course of a year1 a horizontal line one yard in length2 so that #bdj cubic inches would cross a line #ajj yards in length4 ,this latter amount in a damp state would weigh #aa pounds4 ,thus a considerable weight of earth is continually moving down each side of every valley1 and will in time reach its bed4 ,finally this earth will be transported by the streams flowing in the valleys into the ocean1 the great receptacle for all matter denuded from the land4 ,it is known from the amount of sediment annually delivered into the sea by the ,mississippi1 that its enormous drainage-area must on an average be lowered 4#jjbfc of an inch each year2 and this would suffice in four and half million years to lower the whole drainage-area to the level of the sea-shore4 ,so that1 if a small fraction of the layer of fine earth1 #j4b of an inch in thickness1 which is annually brought to the surface by worms1 is carried away1 a great result cannot fail to be produced within a period which no geologist considers extremely long4 99 99 99 99 99 ,archologists ought to be grateful to worms1 as they protect and preserve for an indefinitely long period every object1 not liable to decay1 which is dropped on the surface of the land1 by burying it beneath their castings4 ,thus1 also1 many elegant and curious tesselated pavements and other ancient remains have been preserved2 though no doubt the worms have in these cases been largely aided by earth washed and blown from the adjoining land1 especially when cultivated4 ,the old tesselated pavements have1 however1 often suffered by having subsided unequally from being unequally undermined by the worms4 ,even old massive walls may be undermined and subside2 and no building is in this respect safe1 unless the foundations lie #f or #g feet beneath the surface1 at a depth at which worms cannot work4 ,it is probable that many monoliths and some old walls have fallen down from having been undermined by worms4 99 99 99 99 99 ,worms prepare the ground #bhd in an excellent manner for the growth of fibrous-rooted plants and for seedlings of all kinds4 ,they periodically expose the mould to the air1 and sift it so that no stones larger than the particles which they can swallow are left in it4 ,they mingle the whole intimately together1 like a gardener who prepares fine soil for his choicest plants4 ,in this state it is well fitted to retain moisture and to absorb all soluble substances1 as well as for the process of nitrification4 ,the bones of dead animals1 the harder parts of insects1 the shells of land-molluscs1 leaves1 twigs1 c41 are before long all buried beneath the accumulated castings of worms1 and are thus brought in a more or less decayed state within reach of the roots of plants4 ,worms likewise drag an infinite number of dead leaves and other parts of plants into their burrows1 partly for the sake of plugging them up and partly as food4 ,the leaves which are dragged into the burrows as food1 after being torn into the finest shreds1 partially digested1 and saturated with the intestinal and urinary secretions1 are commingled with much earth4 ,this earth forms the dark coloured1 rich humus which almost everywhere covers the surface of the land with a fairly well-defined layer or mantle4 ,hensen #bhe placed two worms in a vessel #ah inches in diameter1 which was filled with sand1 on which fallen leaves were strewed2 and these were soon dragged into their burrows to a depth of #c inches4 ,after about #f weeks an almost uniform layer of sand1 a centimeter 7#j4d inch7 in thickness1 was converted into humus by having passed through the alimentary canals of these two worms4 ,it is believed by some persons that worm-burrows1 which often penetrate the ground almost perpendicularly to a depth of #e or #f feet1 materially aid in its drainage2 notwithstanding that the viscid castings piled over the mouths of the burrows prevent or check the rain-water directly entering them4 ,they allow the air to penetrate deeply into the ground4 ,they also greatly facilitate the downward passage of roots of moderate size2 and these will be nourished by the humus with which the burrows are lined4 ,many seeds owe their germination to having been covered by castings2 and others buried to a considerable depth beneath accumulated castings lie dormant1 until at some future time they are accidentally uncovered and germinate4 ,worms are poorly provided with sense-organs1 for they cannot be said to see1 although they can just distinguish between light and darkness2 they are completely deaf1 and have only a feeble power of smell2 the sense of touch alone is well developed4 ,they can therefore learn but little about the outside world1 and it is surprising that they should exhibit some skill in lining their burrows with their castings and with leaves1 and in the case of some species in piling up their castings into tower-like constructions4 ,but it is far more surprising that they should apparently exhibit some degrees of intelligence instead of a mere blind instinctive impulse1 in their manner of plugging up the mouths of their burrows4 ,they act in nearly the same manner as would a man1 who had to close a cylindrical tube with different kinds of leaves1 petioles1 triangles of paper1 c41 for they commonly seize such objects by their pointed ends4 ,but with thin objects a certain number are drawn in by their broader ends4 ,they do not act in the same unvarying manner in all cases1 as do most of the lower animals2 for instance1 they do not drag in leaves by their foot-stalks1 unless the basal part of the blade is as narrow as the apex1 or narrower than it4 99 99 99 99 99 ,when we behold a wide1 turf-covered expanse1 we should remember that its smoothness1 on which so much of its beauty depends1 is mainly due to all the inequalities having been slowly levelled by worms4 ,it is a marvellous reflection that the whole of the superficial mould over any such expanse has passed1 and will again pass1 every few years through the bodies of worms4 ,the plough is one of the most ancient and most valuable of man's inventions2 but long before he existed the land was in fact regularly ploughed1 and still continues to be thus ploughed by earth-worms4 ,it may be doubted whether there are many other animals which have played so important a part in the history of the world1 as have these lowly organized creatures4 ,some other animals1 however1 still more lowly organized1 namely corals1 have done far more conspicuous work in having constructed innumerable reefs and islands in the great oceans2 but these are almost confined to the tropical zones4 ,,footnotes4 #b #8,leons de ,gologie ,pratique1' tom4 i4 #ahde1 p4 #adj4 #c #8,transactions ,geolog4 ,soc4' vol4 v4 p4 #eje4 ,read ,november #a1 #ahcg4 #d;a #8,histoire des progrs de la ,gologie1' tom4 i4 #ahdg1 p4 #bbd4 #d;b #8,zeitschrift fr wissenschaft4 ,zoologie1' ,b4 xxviii4 #ahgg1 p4 #cfa4 #e #8,gardeners' ,chronicle1' ,april #ag1 #ahfi1 p4 #dah4 #f ,mr4 ,darwin's attention was called by ,professor ,hensen to ,p4 ,e4 ,mller's work on ,humus in #8,tidsskrift for ,skovbrug1' ,band iii4 ,heft #a and #b1 ,copenhagen1 #ahgh4 ,he had1 however1 no opportunity of consulting ,mller's work4 ,dr4 ,mller published a second paper in #ahhd in the same periodical--a ,danish journal of forestry4 ,his results have also been published in ,german1 in a volume entitled #8,studien ber die natrlichen ,humusformen1 unter deren ,einwirkung auf ,vegetation und ,boden1' #hvo41 ,berlin1 #ahhg4 #h;a #8,bidrag till ,skandinaviens ,oligochtfauna1' #ahga4 #h;b #8,die bis jetzt bekannten ,arten aus der ,familie der ,regenwrmer1' #ahde4 #i;b ,there is even some reason to believe that pressure is actually favourable to the growth of grasses1 for ,professor ,buckman1 who made many observations on their growth in the experimental gardens of the ,royal ,agricultural ,college1 remarks 7#8,gardeners' ,chronicle1' #ahed1 p4 #fai73 8,another circumstance in the cultivation of grasses in the separate form or small patches1 is the impossibility of rolling or treading them firmly1 without which no pasture can continue good40 #aa ,i shall have occasion often to refer to ,m4 ,perrier's admirable memoir1 #8,organisation des ,lombriciens terrestres' in #8,archives de ,zoolog4 expr4' tom4 iii4 #ahgd1 p4 #cgb4 ,c4 ,f4 ,morren 7#8,de ,lumbrici terrestris ,hist4 ,nat4' #ahbi1 p4 #ad7 found that worms endured immersion for fifteen to twenty days in summer1 but that in winter they died when thus treated4 #ab ,morren1 #8,de ,lumbrici terrestris ,hist4 ,nat4' c41 #ahbi1 p4 #fg4 #ad #8,de ,lumbrici terrestris ,hist4 ,nat4' c41 p4 #ad4 #ag ,histolog4 ,untersuchungen ber die ,regenwrmer4 #8,zeitschrift fr wissenschaft4 ,zoologie1' ,b4 xix41 #ahfi1 p4 #faa4 #ah;a ,for instance1 ,mr4 ,bridgman and ,mr4 ,newman 7#8,the ,zoologist1' vol4 vii4 #ahdi1 p4 #begf71 and some friends who observed worms for me4 #ah;b #8,familie der ,regenwrmer1' #ahde1 p4 #ah4 #ca #8,the ,zoologist1' vol4 vii4 #ahdi1 p4 #begf4 #cb #8,familie der ,regenwrmer1' p4 #ac4 ,dr4 ,sturtevant states in the #8,new ,york ,weekly ,tribune' 7,may #ai1 #ahhj7 that he kept three worms in a pot1 which was allowed to become extremely dry2 and these worms were found 8all entwined together1 forming a round mass and in good condition40 #cc #8,de ,lumbrici terrestris ,hist4 ,nat4' p4 #ai4 #cd #8,archives de ,zoologie exprimentale1' tom4 vii4 #ahgh1 p4 #cid4 ,when ,i wrote the above passage1 ,i was not aware that ,krukenberg 7#8,untersuchungen a4 d4 physiol4 ,inst4 d4 ,univ4 ,heidelberg1' ,bd4 ii4 p4 #cg1 #ahgg7 had previously investigated the digestive juice of ,lumbricus4 ,he states that it contains a peptic1 and diastatic1 as well as a tryptic ferment4 #ce;a ,on the action of the pancreatic ferment1 see #8,a ,text-,book of ,physiology1' by ,michael ,foster1 #bnd edit4 pp4 #aih-bjc4 #ahgh4 #ce;b ,schmulewitsch1 #8,action des ,sucs digestifs sur la ,cellulose4' ,bull4 de l',acad4 ,imp4 de ,st4 ,ptersbourg1 tom4 xxv4 p4 #edi4 #ahgi4 #dj ,claparde doubts whether saliva is secreted by worms3 see #8,zeitschrift fr wissenschaft4 ,zoologie1' ,b4 xix4 #ahfi1 p4 #fja4 #da;a ,perrier1 #8,archives de ,zoolog4 expr4' ,july1 #ahgd1 pp4 #daf1 #dai4 #da;b #8,zeitschrift fr wissenschaft4 ,zoologie1' ,b4 xix1 #ahfi1 pp4 #fjc-fjf4 #df ,de ,vries1 #8,landwirth4 ,jahrbcher1' #ahha1 p4 #gg4 #di ,m4 ,foster1 #8,a ,text-,book of ,physiology1' #bnd edit4 #ahgh1 p4 #bdc4 #ej ,m4 ,foster1 ut sup4 p4 #bjj4 #ec ,claparde remarks 7#8,zeitschrift fr wisseuschaft4 ,zoolog4' ,b4 #ai1 #ahfi1 p4 #fjb7 that the pharynx appears from its structure to be adapted for suction4 #eh ,an account of her observations is given in the #8,gardeners' ,chronicle1' ,march #bhth1 #ahfh1 p4 #cbd4 #ei;a ,london's #8,gard4 ,mag4' xvii4 p4 #baf1 as quoted in the #8,catalogue of the ,british ,museum ,worms1' #ahfe1 p4 #cbg4 #ei;b #8,familie der ,regenwrmer1' p4 #ai4 #gi ,in these narrow triangles the apical angle is #i #cd1 and the basal angles #he #ac4 ,in the broader triangles the apical angle is #ai #aj and the basal angles #hj #be4 #hi;a ,see his interesting work1 #8,souvenirs entomologiques1' #ahgi1 pp4 #afh-agg4 #hi;b ,mbius1 #8,die ,bewegungen der ,thiere1' c41 #ahgc1 p4 #aaa4 #ij #8,annals and ,mag4 of ,n4 ,history1' series ii4 vol4 ix4 #aheb1 p4 #ccc4 #ic #8,archives de ,zoolog4 expr4' tom4 iii4 #ahgd1 p4 #dje4 #ig ,i state this on the authority of ,semper1 #8,reisen im ,archipel der ,philippinen1' ,th4 ii4 #ahgg1 p4 #cj4 #aja ,dr4 ,king gave me some worms collected near ,nice1 which1 as he believes1 had constructed these castings4 ,they were sent to ,m4 ,perrier1 who with great kindness examined and named them for me3 they consisted of ,perichta affinis1 a native of ,cochin ,china and of the ,philippines2 ,p4 ,luzonica1 a native of ,luzon in the ,philippines2 and ,p4 ,houlleti1 which lives near ,calcutta4 ,m4 ,perrier informs me that species of ,perichta have been naturalized in the gardens near ,montpellier and in ,algiers4 ,before ,i had any reason to suspect that the tower-like castings from ,nice had been formed by worms not endemic in the country1 ,i was greatly surprised to see how closely they resembled castings sent to me from near ,calcutta1 where it is known that species of ,perichta abound4 #ajb #8,zeitschrift fr wissenschaft4 ,zoolog4' ,b4 xxviii4 #ahgg1 p4 #cfd4 #ajh #8,zeitschrift fr wissenschaft4 ,zoolog4' ,b4 xxviii4 #ahgg1 p4 #cef4 #aac ,perrier1 #8,archives de ,zoolog4 expr4' tom4 #c1 p4 #cgh1 #ahgd4 #abf ,this case is given in a postscript to my paper in the #8,transact4 ,geolog4 ,soc4' 7,vol4 v4 p4 #eje71 and contains a serious error1 as in the account received ,i mistook the figure #cj for #hj4 ,the tenant1 moreover1 formerly said that he had marled the field thirty years before1 but was now positive that this was done in #ahji1 that is twenty-eight years before the first examination of the field by my friend4 ,the error1 as far as the figure #hj is concerned1 was corrected in an article by me1 in the #8,gardeners' ,chronicle1' #ahdd1 p4 #bah4 #abh ,these pits or pipes are still in process of formation4 ,during the last forty years ,i have seen or heard of five cases1 in which a circular space1 several feet in diameter1 suddenly fell in1 leaving on the field an open hole with perpendicular sides1 some feet in depth4 ,this occurred in one of my own fields1 whilst it was being rolled1 and the hinder quarters of the shaft horse fell in2 two or three cart-loads of rubbish were required to fill up the hole4 ,the subsidence occurred where there was a broad depression1 as if the surface had fallen in at several former periods4 ,i heard of a hole which must have been suddenly formed at the bottom of a small shallow pool1 where sheep had been washed during many years1 and into which a man thus occupied fell to his great terror4 ,the rain-water over this whole district sinks perpendicularly into the ground1 but the chalk is more porous in certain places than in others4 ,thus the drainage from the overlying clay is directed to certain points1 where a greater amount of calcareous matter is dissolved than elsewhere4 ,even narrow open channels are sometimes formed in the solid chalk4 ,as the chalk is slowly dissolved over the whole country1 but more in some parts than in others1 the undissolved residue--that is the overlying mass of red clay with flints1--likewise sinks slowly down1 and tends to fill up the pipes or cavities4 ,but the upper part of the red clay holds together1 aided probably by the roots of plants1 for a longer time than the lower parts1 and thus forms a roof1 which sooner or later falls in1 as in the above mentioned five cases4 ,the downward movement of the clay may be compared with that of a glacier1 but is incomparably slower2 and this movement accounts for a singular fact1 namely1 that the much elongated flints which are embedded in the chalk in a nearly horizontal position1 are commonly found standing nearly or quite upright in the red clay4 ,this fact is so common that the workmen assured me that this was their natural position4 ,i roughly measured one which stood vertically1 and it was of the same length and of the same relative thickness as one of my arms4 ,these elongated flints must get placed in their upright position1 on the same principle that a trunk of a tree left on a glacier assumes a position parallel to the line of motion4 ,the flints in the clay which form almost half its bulk1 are very often broken1 though not rolled or abraded2 and this may be accounted for by their mutual pressure1 whilst the whole mass is subsiding4 ,i may add that the chalk here appears to have been originally covered in parts by a thin bed of fine sand with some perfectly rounded flint pebbles1 probably of ,tertiary age2 for such sand often partly fills up the deeper pits or cavities in the chalk4 #aca ,s4 ,w4 ,johnson1 #8,how ,crops ,feed1' #ahgj1 p4 #aci4 #acf;a #8,nature1' ,november #ahgg1 p4 #bh4 #acf;b #8,proc4 ,phil4 ,soc4' of ,manchester1 #ahgg1 p4 #bdg4 #ach;a #8,trans4 of the ,new ,zealand ,institute1' vol4 xii41 #ahhj1 p4 #aeb4 #ach;b ,mr4 ,lindsay ,carnagie1 in a letter 7,june #ahch7 to ,sir ,c4 ,lyell1 remarks that ,scotch farmers are afraid of putting lime on ploughed land until just before it is laid down for pasture1 from a belief that it has some tendency to sink4 ,he adds3 8,some years since1 in autumn1 ,i laid lime on an oat-stubble and ploughed it down2 thus bringing it into immediate contact with the dead vegetable matter1 and securing its thorough mixture through the means of all the subsequent operations of fallow4 ,in consequence of the above prejudice1 ,i was considered to have committed a great fault2 but the result was eminently successful1 and the practice was partially followed4 ,by means of ,mr4 ,darwin's observations1 ,i think the prejudice will be removed40 #aci ,this conclusion1 which1 as we shall immediately see1 is fully justified1 is of some little importance1 as the so-called bench-stones1 which surveyors fix in the ground as a record of their levels1 may in time become false standards4 ,my son ,horace intends at some future period to ascertain how far this has occurred4 #adg ,mr4 ,r4 ,mallet remarks 7#8,quarterly ,journal of ,geolog4 ,soc4' vol4 xxxiii41 #ahgg1 p4 #gde7 that 8the extent to which the ground beneath the foundations of ponderous architectural structures1 such as cathedral towers1 has been known to become compressed1 is as remarkable as it is instructive and curious4 ,the amount of depression in some cases may be measured by feet40 ,he instances the ,tower of ,pisa1 but adds that it was founded on 8dense clay40 #adh #8,zeitschrift fr wissensch4 ,zoolog4' ,bd4 xxviii41 #ahgg1 p4 #cfj4 #adi ,see ,mr4 ,dancer's paper in #8,proc4 ,phil4 ,soc4 of ,manchester1' #ahgg1 p4 #bdh4 #aff;a #8,leons de ,gologie pratique1' #ahde1 p4 #adb4 #aff;b ,a short account of this discovery was published in #8,the ,times' of ,january #b1 #ahgh2 and a fuller account in #8,the ,builder1' ,january #e1 #ahgh4 #ahc ,several accounts of these ruins have been published2 the best is by ,mr4 ,james ,farrer in #8,proc4 ,soc4 of ,antiquaries of ,scotland1' vol4 vi41 ,part ,,ii41 #ahfg1 p4 #bgh4 ,also ,j4 ,w4 ,grover1 #8,journal of the ,british ,arch4 ,assoc4' ,june #ahff4 ,professor ,buckman has likewise published a pamphlet1 #8,notes on the ,roman ,villa at ,chedworth1' #bnd edit4 #ahgc ,cirencester4 #ahg ,these details are taken from the #8,penny ,cyclopdia1' article ,hampshire4 #baj 8,on the denudation of ,south ,wales10 c41 #8,memoirs of the ,geological ,survey of ,great ,britain1' vol4 #a41 p4 #big1 #ahdf4 #baa #8,geological ,magazine1' ,october and ,november1 #ahfg1 vol4 iv4 pp4 #ddg and #dhc4 ,copious references on the subject are given in this remarkable memoir4 #bab ,a4 ,tylor 8,on changes of the sea-level10 c41 #8 ,philosophical ,mag4' 7,ser4 #dth7 vol4 v41 #ahec1 p4 #beh4 ,archibald ,geikie1 ,transactions ,geolog4 ,soc4 of ,glasgow1 vol4 iii41 p4 #aec 7read ,march1 #ahfh74 ,croll 8,on ,geological ,time10 #8,philosophical ,mag41' ,may1 ,august1 and ,november1 #ahfh4 ,see also ,croll1 #8,climate and ,time1' #ahge1 ,chap4 ,,xx4 ,for some recent information on the amount of sediment brought down by rivers1 see #8,nature1' ,sept4 #bcrd1 #ahhj4 ,mr4 ,t4 ,mellard ,reade has published some interesting articles on the astonishing amount of matter brought down in solution by rivers4 ,see ,address1 ,geolog4 ,soc41 ,liverpool1 #ahgf-gg4 #bac 8,an account of the fine dust which often falls on ,vessels in the ,atlantic ,ocean10 ,proc4 ,geolog4 ,soc4 of ,london1 ,june #dth1 #ahde4 #bae ,for ,la ,plata1 see my #8,journal of ,researches1' during the voyage of the ,beagle1 #ahde1 p4 #acc4 lie de ,beaumont has given 7#8,leons de ,golog4 pratique1' tom4 ,i4 #ahde1 p4 #ahc7 an excellent account of the enormous quantity of dust which is transported in some countries4 ,i cannot but think that ,mr4 ,proctor has somewhat exaggerated 7#8,pleasant ,ways in ,science1' #ahgi1 p4 #cgi7 the agency of dust in a humid country like ,great ,britain4 ,james ,geikie has given 7#8,prehistoric ,europe1' #ahhj1 p4 #afe7 a full abstract of ,richthofen's views1 which1 however1 he disputes4 #bag;a ,these statements are taken from ,hensen in #8,zeitschrift fr wissenschaft4 ,zoologie4' ,bd4 xxviii41 #ahgg1 p4 #cfj4 ,those with respect to peat are taken from ,mr4 ,a4 ,a4 ,julien in #8,proc4 ,american ,assoc4 ,science1' #ahgi1 p4 #ced4 #bag;b ,i have given some facts on the climate necessary or favourable for the formation of peat1 in my #8,journal of ,researches1' #ahde1 p4 #bhg4 #bbj ,a4 ,a4 ,julien 8,on the ,geological action of the ,humus-acids10 #8,proc4 ,american ,assoc4 ,science1' vol4 xxviii41 #ahgi1 p4 #caa4 ,also on 8,chemical erosion on ,mountain ,summits20 #8,new ,york ,academy of ,sciences1' ,oct4 #ad1 #ahgh1 as quoted in the #8,american ,naturalist4' ,see also1 on this subject1 ,s4 ,w4 ,johnson1 #8,how ,crops ,feed1' #ahgj1 p4 #ach4 #bbb ,see1 for references on this subject1 ,s4 ,w4 ,johnson1 #8,how ,crops ,feed1' #ahgj1 p4 #cbf4 #bbc ,this statement is taken from ,mr4 ,julien1 #8,proc4 ,american ,assoc4 ,science1' vol4 xxviii41 #ahgi1 p4 #ccj4 #bbd;a ,the preservative power of a layer of mould and turf is often shown by the perfect state of the glacial scratches on rocks when first uncovered4 ,mr4 ,j4 ,geikie maintains1 in his last very interesting work 7#8,prehistoric ,europe1' #ahha71 that the more perfect scratches are probably due to the last access of cold and increase of ice1 during the long-continued1 intermittent glacial period4 #bbd;b ,many geologists have felt much surprise at the complete disappearance of flints over wide and nearly level areas1 from which the chalk has been removed by subaerial denudation4 ,but the surface of every flint is coated by an opaque modified layer1 which will just yield to a steel point1 whilst the freshly fractured1 translucent surface will not thus yield4 ,the removal by atmospheric agencies of the outer modified surfaces of freely exposed flints1 though no doubt excessively slow1 together with the modification travelling inwards1 will1 as may be suspected1 ultimately lead to their complete disintegration1 notwithstanding that they appear to be so extremely durable4 #bbe;a #8,archives de ,zoolog4 expr4' tom4 iii4 #ahgd1 p4 #dji4 #bbe;b #8,nouvelles ,archives du ,musum1' tom4 viii4 #ahgb1 pp4 #ie1 #aca4 #bbf ,morren1 in speaking of the earth in the alimentary canals of worms1 says1 8prsep cum lapillis commixtam vidi30 #8,de ,lumbrici terrestris ,hist4 ,nat4' c41 #ahbi1 p4 #af4 #bbg ,perrier1 #8,archives de ,zoolog4 expr4' tom4 iii4 #ahgd1 p4 #dai4 #bbh;a ,morren1 #8,de ,lumbrici terrestris ,hist4 ,nat4' c41 p4 #af4 #bbh;b #8,archives de ,zoolog4 expr4' tom4 iii4 #ahgd1 p4 #dah4 #bcd ,this conclusion reminds me of the vast amount of extremely fine chalky mud which is found within the lagoons of many atolls1 where the sea is tranquil and waves cannot triturate the blocks of coral4 ,this mud must1 as ,i believe 7#8,the ,structure and ,distribution of ,coral-,reefs1' #bnd edit4 #ahgd1 p4 #ai71 be attributed to the innumerable annelids and other animals which burrow into the dead coral1 and to the fishes1 ,holothurians1 c41 which browse on the living corals4 #bcf ,anniversary ,address3 #8,the ,quarterly ,journal of the ,geological ,soc4' ,may #ahhj1 p4 #ei4 #bdd ,mr4 ,james ,wallace has pointed out that it is necessary to take into consideration the possibility of burrows being made at right angles to the surface instead of vertically down1 in which case the lateral displacement of the soil would be increased4 #bei #8,elements of ,geology1' #ahfe1 p4 #bj4 #bfe #8,leons de ,gologie pratique1 #ahde2 cinquime ,leon4 ,all lie de ,beaumont's arguments are admirably controverted by ,prof4 ,a4 ,geikie in his essay in ,transact4 ,geolog4 ,soc4 of ,glasgow1 vol4 iii4 p4 #aec1 #ahfh4 #bff #8,illustrations of the ,huttonian ,theory of the ,earth1' p4 #ajg4 #bfi ,mr4 ,e4 ,tylor in his ,presidential address 7#8,journal of the ,anthropological ,institute1' ,may #ahhj1 p4 #dea7 remarks3 8,it appears from several papers of the ,berlin ,society as to the ,german #8high-fields' or #8heathen-fields' 7,hochcker1 and ,heidencker7 that they correspond much in their situation on hills and wastes with the #8elf-furrows' of ,scotland1 which popular mythology accounts for by the story of the fields having been put under a ,papal interdict1 so that people took to cultivating the hills4 ,there seems reason to suppose that1 like the tilled plots in the ,swedish forest which tradition ascribes to the old #8hackers1' the ,german heathen-fields represent tillage by an ancient and barbaric population40 #bhd ,white of ,selborne has some good remarks on the service performed by worms in loosening1 c41 the soil4 ,edit1 by ,l4 ,jenyns1 #ahdc1 p4 #bha4 #bhe #8,zeitschrift fr wissenschaft4 ,zoolog4' ,b4 xxviii4 #ahgg1 p4 #cfj4