,transcriber's ,note3 ,italic text delimited by underscores4 ,the ,cambridge ,manuals of ,science and ,literature ,,the ,,story ,,of ,a ,,loaf ,,of ,,bread ,,cambridge ,,university ,,press ,london3 ,,fetter ,,lane1 ,e4,c4 ,c4 ,f4 ,,clay1 ,,manager ,illustration ,edinburgh3 #ajj1 ,,princes ,,street ,london3 ,h4 ,k4 ,,lewis1 #acf1 ,,gower ,,street1 ,w4,c4 ,,william ,,wesley ,,son1 #bh1 ,,essex ,,street1 ,,strand ,berlin3 ,a4 ,,asher ,,and ,,co4 ,leipzig3 ,f4 ,a4 ,,brockhaus ,new ,york3 ,g4 ,p4 ,,putnam',s ,,sons ,bombay and ,calcutta3 ,,macmillan ,,and ,,co41 ,ltd4 ,all rights reserved ,illustration3 ,,the ,,story ,,of ,a ,,loaf ,,of ,,bread ,,by ,t4 ,b4 ,,wood1 ,m4,a4 ,drapers ,professor of ,agriculture in the ,university of ,cambridge ,cambridge3 at the ,university ,press ,new ,york3 ,g4 ,p4 ,putnam's ,sons #aiac ,cambridge3 ,,printed ,,by ,,john ,,clay1 ,m4,a4 ,,at ,,the ,,university ,,press ,with the exception of the coat of arms at the foot1 the design on the title page is a reproduction of one used by the earliest known ,cambridge printer1 ,john ,siberch1 #aeba ,,preface ,i have ventured to write this little book with some diffidence1 for it deals with farming1 milling and baking1 subjects on which everyone has his own opinion4 ,in the earlier chapters ,i have tried to give a brief sketch of the growing and marketing of wheat4 ,if ,i have succeeded1 the reader will realise that the farmer's share in the production of the staple food of the people is by no means the simple affair it appears to be4 ,the various operations of farming are so closely interdependent that even the most complex book-keeping may fail to disentangle the accounts so as to decide with certainty whether or not any innovation is profitable4 ,the farmer1 especially the small farmer1 spends his days in the open air1 and does not feel inclined to indulge in analytical book-keeping in the evening4 ,consequently1 the onus of demonstrating the economy of suggested innovations in practice lies with those who make the suggestions4 ,this is one of the many difficulties which confronts everyone who sets out to improve agriculture4 ,in the third and fourth chapters ,i have discussed the quality of wheat4 ,i have tried to describe the investigations which are in progress with the object of improving wheat from the point of view of both the farmer and the miller1 and to give some account of the success with which they have been attended4 ,incidentally ,i have pointed out the difficulties which pursue any investigation which involves the cultivation on the large scale of such a crop as wheat1 and the consequent need of adopting due precautions to ensure accuracy before making recommendations to the farmer4 ,advice based on insufficient evidence is more than likely to be misleading4 ,every piece of misleading advice is a definite handicap to the progress of agricultural science4 ,the fifth chapter is devoted to a short outline of the milling industry4 ,in chapter ,,vi the process of baking is described4 ,in the last two chapters the composition of bread is discussed at some length4 ,i have tried to state definitely and without bias which points in this much debated subject are known with some certainty1 and which points require further investigation4 ,throughout the following pages1 but especially in chapters ,,iii and ,,iv1 ,i have drawn freely upon the work of my colleagues4 ,i am also much indebted to my friends1 ,mr ,a4 ,e4 ,humphries1 the chairman of the ,home ,grown ,wheat ,committee1 and ,mr ,e4 ,s4 ,beaven of ,warminster1 whose advice has always been at my disposal4 ,a list of publications on the various branches of the subject will be found at the end of the volume4 ,t4 ,b4 ,w4 ,,gonville ,,and ,,caius ,,college1 ,,cambridge4 #c ,december1 #aiab4 ,,contents ,,chap4 ,,page ,preface v ,i4 ,wheat-growing #a ,,ii4 ,marketing #ae ,,iii4 ,the quality of wheat #bg ,,iv4 ,the quality of wheat from the miller's point of view #ea ,v4 ,the milling of wheat #gd ,,vi4 ,baking #ia ,,vii4 ,the composition of bread #ajh ,,viii4 ,concerning different kinds of bread #abj ,bibliography #acf ,index #aci ,,list ,,of ,,illustrations ,,fig4 ,,page #a4 ,typical ears of wheat #cj #b4 ,bird-proof enclosure for variety testing #cd #c4 ,a wheat flower to illustrate the method of cross-fertilising #da #d4 ,parental types and first and second generation #dc #e4 ,parent varieties in bird-proof enclosure #dh #f4 ,testing new varieties in the field #ej #g4 ,loaves made from ,manitoba wheat #ed #h4 ,loaves made from ,english wheat #ed #i4 ,loaves made from ,rivet wheat #ee #aj4 ,loaves made from ,manitoba wheat1 ,english wheat1 and ,manitoba-,english hybrid1 ,burgoyne's ,fife #ei #aa4 ,gluten in water and acid #fi #ab4 ,gluten in water containing both acid and salts #ga #ac4 ,end view of break rolls #ha #ad4 ,break rolls showing gearing #hb #ae4 ,reduction rolls #hg #af4 ,baking test3 loaves rising in incubator #ib #ag4 ,baking test3 loaves leaving the oven #ic ,,the ,,story ,,of ,a ,,loaf ,,of ,,bread ,,chapter ,i ,,wheat ,,growing ,wheat is one of the most adaptable of plants4 ,it will grow on almost any kind of soil1 and in almost any temperate climate4 ,but the question which concerns the wheat grower is not whether he can grow wheat1 but whether he can grow it profitably4 ,this is a question of course that can never receive a final answer4 ,any increase in the price of wheat1 or any improvement that lowers the cost of cultivation1 may enable growers who cannot succeed under present conditions to grow wheat at a profit4 ,thus if the population of the world increases1 and wheat becomes scarce1 the wheat-growing area will doubtless be extended to districts where wheat cannot be grown profitably under present conditions4 ,a study of the history of wheat-growing in this country during the last century shows that the reverse of this took place4 ,in the first half of that period the population had increased1 and from lack of transport facilities and other causes the importation of foreign wheat was small4 ,prices were high in consequence and every acre of available land was under wheat4 ,as transport facilities increased wheat-growing areas were developed in ,canada1 in the ,western ,states of ,america1 in the ,argentine1 and in ,australia1 and the importation of foreign wheat increased enormously4 ,this led to a rapid decrease in prices1 and wheat-growing had to be abandoned on all but the most suitable soils in the ,british ,isles4 ,from #ahhj onwards thousands of acres of land which had grown wheat profitably for many years were laid down to grass4 ,in the last decade the world's population has increased faster than the wheat-growing area has been extended4 ,prices have consequently risen1 and the area under wheat in the ,british ,isles will no doubt increase4 ,but although it cannot be stated with finality on what land wheat can be grown1 or cannot be grown1 at a profit1 nevertheless accumulated experience has shown that wheat grows best on the heavier kinds of loam soils where the rainfall is between #bj and #cj inches per annum4 ,it grows nearly as well on clay soils and on lighter loams1 and with the methods of dry farming followed in the arid regions of the ,western ,states and ,canada1 it will succeed with less than its normal amount of rainfall4 ,it is now about a hundred years since chemistry was applied with any approach to exactitude to questions affecting agriculture2 since for instance it was first definitely recognised that plants must obtain from their surroundings the carbon1 hydrogen1 oxygen1 nitrogen1 phosphorus1 sulphur1 potassium1 calcium1 and other elements of which their substance is composed4 ,for many years there was naturally much uncertainty as to the source from which these several elements were derived4 ,experiment soon showed that carbon was undoubtedly taken from the air1 and that its source was the carbon dioxide poured into the air by fires and by the breathing of animals4 ,it soon became obvious too that plants obtain from the soil water and inorganic salts containing phosphorus1 sulphur1 potassium1 calcium1 and so on2 but for a long time the source of the plants' supply of nitrogen was not definitely decided4 ,four-fifths of the air was known to be nitrogen4 ,the soil was known to contain a small percentage of that element1 which however amounts to four or five tons per acre4 ,which was the source of the plants' nitrogen could be decided only by careful experiment4 ,as late as #ahdj ,liebig1 perhaps the greatest chemist of his day1 wrote a book on the application of chemistry to agriculture4 ,in it he stated that plants could obtain from the air all the nitrogen they required1 and that1 to produce a full crop1 it was only necessary to ensure that the soil should provide a sufficient supply of the mineral elements1 as he called them1 phosphorus1 potassium1 calcium1 etc4 ,now of all the elements which the farmer has to buy for application to his land as manure1 nitrogen is the most costly4 ,at the present time nitrogen in manures costs sevenpence per pound1 whilst a pound of phosphorus in manures can be bought for fivepence1 and a pound of potassium for twopence4 ,the importance of deciding whether it is necessary to use nitrogen in manures needs no further comment4 ,it was to settle definitely questions like this that ,john ,bennet ,lawes began his experiments at his home at ,rothamsted1 near ,harpenden in ,hertfordshire1 on the manuring of crops4 ,these experiments were started almost simultaneously with the publication of ,liebig's book1 and many of ,lawes' original plots laid out over #gj years ago are still in existence4 ,the results which he obtained in collaboration with his scientific colleague1 ,joseph ,henry ,gilbert1 soon overthrew ,liebig's mineral theory of manuring1 and showed that in order to grow full crops of wheat it is above all things necessary to ensure that the soil should be able to supply plenty of nitrogen4 ,thus it was found that the soil of the ,rothamsted ,experiment ,station was capable of growing wheat continuously year after year4 ,with no manure the average crop was only about #ac bushels per acre4 ,the addition of a complete mineral manure containing phosphorus1 calcium1 potassium1 in fact all the plant wants from the soil except nitrogen1 only increased the crop to #ae bushels per acre4 ,manuring with nitrogen on the other hand increased the crop to #ba bushels per acre4 ,obviously on the ,rothamsted soil wheat has great difficulty in getting all the nitrogen it wants1 but is well able to fend for itself as regards what ,liebig called minerals4 ,this kind of experiment has been repeated on almost every kind of soil in the ,united ,kingdom1 and it is found that the inability of wheat to supply itself with nitrogen applies to all soils1 except the black soils of the ,fens which contain about ten times more nitrogen than the ordinary arable soils of the country4 ,it is the richness in nitrogen of the virgin soils of the ,western ,states and ,canada1 and of the black soils of ,russia1 that forms one of the chief factors in their success as wheat-growing lands4 ,it must be added1 however1 that continuous cropping without manure must in time exhaust the stores of nitrogen in even the richest soil1 and when this time comes the farmers in these at present favoured regions will undoubtedly find wheat-growing more costly by whatever sum per acre they may find it necessary to expend in nitrogenous manure4 ,the world's demand for nitrogenous manure is therefore certain to increase4 ,such considerations as these inspired ,sir ,william ,crookes' ,presidential address to the ,british ,association in #ahih1 in which he foretold the probability of a nitrogen famine1 and explained how it must lead to a shortage in the world's wheat supply4 ,the remedy he suggested was the utilization of water-power to provide the energy for generating electricity1 by means of which the free nitrogen of the air should be brought into combination in such forms that it could be used for manure4 ,it is interesting to note that these suggestions have been put into practice4 ,in ,norway1 in ,germany1 and in ,america waterfalls have been made to drive dynamos1 and the electricity thus generated has been used to make two new nitrogenous manures1 calcium nitrate and calcium cyanamide1 which are now coming on to the market at prices which will compete with sulphate of ammonia from the gas works1 nitrate of soda from ,chili1 ,peruvian guano1 and the various plant and animal refuse materials which have up to the present supplied the farmer with his nitrogenous manures4 ,this is welcome news to the wheat grower1 for the price of manurial nitrogen has steadily risen during the last decade4 ,before leaving the question of manuring one more point from the ,rothamsted experiments must be referred to4 ,it has already been mentioned that when manured with nitrogen alone the ,rothamsted soil produced #ba bushels of wheat per acre4 ,when1 however1 a complete manure containing both nitrogen and minerals was used the crop rose to #ce bushels per acre which is about the average yield per acre of wheat in ,england4 ,this shows that although the yield of wheat is dependent in the first place on the nitrogen supplied by the soil1 it is still far from independent of a proper supply of minerals4 ,a further experiment on this point showed that minerals are not used up by the crop to which they are applied1 and that any excess left over remains in the soil for next year4 ,this is not the case with nitrogenous manures4 ,whatever is left over from one crop is washed out of the soil by the winter rains1 and lost4 ,translated into farm practice these results mean that nitrogenous manures should be applied direct to the wheat crop1 but that wheat may as a rule be trusted to get all the minerals it wants from the phosphate and potash applied directly to other crops which are specially dependent on an abundant supply of these substances4 ,at ,rothamsted1 ,lawes and ,gilbert adopted the practice of growing wheat continuously on the same land year after year in order to find out as quickly as possible the manurial peculiarities of the crop4 ,this however is not the general system of the ,british farmer1 but it has been carried out with commercial success by ,mr ,prout of ,sawbridgeworth in ,hertfordshire4 ,the ,sawbridgeworth farm is heavy land on the ,london clay4 ,mr ,prout's system was to cultivate the land by steam power1 to manure on the lines suggested by the ,rothamsted experiments1 and to sell both grain and straw4 ,wheat was grown continuously year after year until the soil became infested with weeds1 when some kind of root crop was grown to give an opportunity to clean the land4 ,a root crop is not sown until ,june so that the land is bare for cleaning all the spring and early summer4 ,such crops also are grown in rows two feet or more apart1 and cultural implements can be used between the rows of plants until the latter cover the soil by the end of ,july or ,august4 ,after cleaning the land in this way the roots are removed from the land in the winter and used to feed the stock4 ,by this time it is too late to sow wheat1 so a barley crop is sown the following spring1 and with the barley clover is sown4 ,clover is an exception to the rule that crops must get their nitrogen from the soil4 ,on the roots of clover1 and other plants of the same botanical order1 such as lucerne1 sainfoin1 beans and peas1 many small swellings are to be found4 ,these swellings1 or nodules as they are usually called1 are produced by bacteria which possess the power of abstracting free nitrogen from the air and transforming it into combined nitrogen in such a form that the clover or other host-plant can feed on it4 ,the clover and the bacteria live in ,symbiosis1 or in other words in a kind of mutual partnership4 ,the host provides the bacteria with a home and allows them to feed on the sugar and other food substances in its juices1 and they in return manufacture nitrogen for the use of the host4 ,when the clover is cut for hay1 its roots are left in the soil1 and in them is a large store of nitrogen derived from the air4 ,a clover crop thus enriches the soil in nitrogen and is the best of all preparations for wheat-growing4 ,after the clover1 wheat was grown again year after year until it once more became necessary to clean the land4 ,this system of wheat-growing was carried on at ,sawbridgeworth for many years with commercial success4 ,it never spread through the country because its success depends on the possibility of finding a remunerative market for the straw4 ,the bulk of straw is so great compared with its price that it cannot profitably be carried to any considerable distance4 ,the only market for straw in quantity is a large town1 and there is no considerable area of land suitable for wheat-growing near a sufficiently large town to provide a market for the large output of straw which would result from such a system of farming4 ,the ordinary practice of the ,british farmer is to grow his wheat in rotation with other crops4 ,various rotations are practised to suit the special circumstances of different districts1 one might almost say of special farms4 ,this short account of wheat-growing does not profess to give a complete account of even ,english farming practice4 ,it is only necessary to describe here one rotation in order to give a general idea of the advantages of that form of husbandry4 ,for this purpose it will suffice to describe the ,norfolk or four course rotation4 ,this rotation begins with a root crop1 usually ,swede turnips1 manured with phosphates1 and potash too on the lighter lands4 ,this crop1 as already described1 provides the opportunity of cleaning the land4 ,it produces also a large amount of food for sheep and cattle4 ,part of the roots are left on the land where they are eaten by sheep during the winter4 ,the roots alone are not suitable for a complete diet4 ,they are supplemented by hay and by some kind of concentrated food rich in nitrogen1 usually linseed cake1 the residue left when the oil is pressed from linseed4 ,now an animal only retains in its body about one-tenth of the nitrogen of its diet1 so that nine-tenths of the nitrogen of the roots1 hay and cake consumed by the sheep find their way back to the land4 ,this practice of feeding sheep on the land therefore acts practically as a liberal nitrogenous manuring4 ,the trampling of the soil in a wet condition in the winter also packs its particles closely together1 and increases its water-holding power1 in much the same way as the special cultural methods employed in the arid western ,states under the name of dry farming4 ,the rest of the roots are carted to the homestead for feeding cattle1 usually fattening cattle for beef4 ,again the roots are supplemented by hay1 straw1 and cake of some kind rich in nitrogen4 ,the straw from former crops is used for litter4 ,its tubular structure enables it to soak up the excreta of the animals1 so that the farmyard manure thus produced retains a large proportion of the nitrogen1 and other substances of manurial value1 which the animals fail to retain in their bodies4 ,this farmyard manure is kept for future use as will be seen later4 ,as soon as the sheep have finished eating their share of the turnips they are sold for mutton4 ,it is now too late in the season to sow wheat4 ,the land is ploughed1 but the ploughing is only a shallow one1 so that the water stored in the deeper layers of the soil which have been solidified by the trampling of the sheep may not be disturbed4 ,the surface soil turned up by the plough is pulverised by harrowing until a fine seed-bed is obtained1 and barley is sown early in the spring4 ,clover and grass seeds are sown amongst the barley1 so that they may take firm root whilst the barley is growing and ripening4 ,the barley is harvested in the autumn4 ,the young clover and grasses establish themselves during the autumn and winter1 and produce a crop of hay the following summer4 ,this is harvested towards the end of ,june1 and the aftermath forms excellent autumn grazing for the sheep and cattle which are to be fed the next winter4 ,as soon as harvest is over the farmer hopes for rain to soften the old clover land1 or olland as it is called in ,norfolk1 so that he can plough it for wheat sowing4 ,whilst he is waiting for rain he takes advantage of the solidity of the soil1 produced by the trampling of the stock1 to cart on to the olland the farmyard manure produced during the cattle feeding of the last winter4 ,as soon as the rain comes this is ploughed in1 and the seed-bed for the wheat prepared as quickly as possible4 ,wheat should be sown as soon as may be after the end of ,september1 so that the young plant may come up and establish itself1 while the soil is yet warm from the summer sun1 and before the winter frosts set in4 ,the wheat spends the winter in root development1 and does not make much show above ground until the spring4 ,it is harvested usually some time in ,august4 ,the wheat stubble is ploughed in the autumn and again in the spring1 and between then and ,june1 when the roots are sown1 it undergoes a thorough cleaning4 ,the complete rotation has now been described4 ,it remains only to point out some of its numerous advantages4 ,in the first place the system described provides excellent conditions for growing both wheat and barley in districts where the rainfall is inclined to be deficient1 say from #bj to #be inches per annum1 as it is in the eastern counties1 and on the ,yorkshire wolds4 ,not only is an abundant supply of nitrogen provided for these crops through the medium of the cake purchased for the stock1 but the solidification of the deeper layers of the soil ensures the retention of the winter's rain for the use of the crop during the dry summer4 ,the residue of the phosphates and potash applied to the root crop1 and left in the soil when that crop is removed1 provides for the mineral requirements of the barley and the wheat4 ,thus each crop gets a direct application of the kind of manure it most needs4 ,rotation husbandry also distributes the labour of the farm over the year4 ,after harvest the farmyard manure is carted on to the land4 ,this is followed by wheat sowing4 ,in the winter there is the stock to be fed4 ,the spring brings barley sowing1 the early summer the cleaning of the land for the roots4 ,then follow the hay harvest and the hoeing of the roots1 and by this time corn-harvest comes round once again4 ,it must not be forgotten that each crop the farmer grows is subject to its own pests4 ,on a four course rotation each crop comes on the same field only once in four years4 ,whilst the field is under roots1 barley1 and clover1 the wheat pests are more or less starved for want of food1 and their virulence is thereby greatly diminished4 ,the catalogue of the advantages of rotation of crops is a long one but one more must be mentioned4 ,the variety of products turned out for sale by the rotation farmer ensures him against the danger which pursues the man who puts all his eggs in one basket4 ,the four course farmer produces not only wheat and barley1 but beef and mutton4 ,the fluctuations in price of these products tend to compensate each other4 ,when corn is cheap1 meat may be dear1 and vice vers4 ,thus in the years about #aijj1 when corn was making very low prices1 sheep sold well1 and the profit on sheep-feeding enabled many four course farmers to weather the bad times4 ,the system of wheat-growing above described is an intensive one4 ,the cultivation is thorough1 the soil is kept in good condition by manuring1 or by the use of purchased feeding stuffs1 and the cost of production is comparatively high4 ,such systems of intensive culture prevail in the more densely populated countries1 but the bulk of the world's wheat supply is grown in thinly populated countries1 where the methods of cultivation are extensive4 ,wheat is sown year after year on the same land1 no manure is used1 and tillage is reduced to a minimum4 ,this style of cultivation gradually exhausts the fertility of the richest virgin soil1 and its cropping capacity falls off4 ,as soon as the crop falls below a certain level it ceases to be profitable4 ,no doubt the fertility of the exhausted soil could be restored by suitable cultivation and manuring1 but it is usually the custom to move towards districts which are still unsettled1 and to take up more virgin soil4 ,thus the centre of the area of wheat production in the ,states has moved nearly #gjj miles westward in the last #ej years4 ,,chapter ,,ii ,,marketing ,in the last chapter we have followed the growing of the wheat from seed time to harvest4 ,but when the farmer has harvested his corn his troubles are by no means over4 ,he has still to thrash it1 dress it1 sell it1 and deliver it to the mill or to the railway station4 ,in the good old times a hundred years ago thrashing was done by the flail1 and found work during the winter for many skilled labourers4 ,this time-consuming method has long disappeared4 ,in this country all the corn is now thrashed by machines1 driven as a rule by steam1 but still in some places by horse-gearing4 ,the thrashing machine1 like all other labour saving devices1 when first introduced was bitterly opposed by the labourers1 who feared that they might lose their winter occupation and the wages it brought them4 ,in the life of ,coke of ,norfolk1 the first ,lord ,leicester1 there is a graphic account of the riots which took place when the first thrashing machine was brought into that county4 ,only the larger farmers possess their own machines4 ,the thrashing on the smaller farms is done by machines belonging to firms of engineers1 which travel the country1 each with its own team of men4 ,these machines will thrash out more than #ajj bags of wheat or barley in a working day4 ,the more modern machines dress the corn so that it is ready for sale without further treatment4 ,after it is thrashed the wheat is carried in sacks into the barn and poured on to the barn floor4 ,it is next winnowed or dressed1 again by a machine1 which subjects it to a process of sifting and blowing in order to remove chaff1 weed-seeds and dirt4 ,as it comes from the dressing machine it is measured into bags1 each of which is weighed and made up to a standard weight ready for delivery4 ,in the meantime the farmer has taken a sample of the wheat to market4 ,the selling of wheat takes place on market day in the corn hall1 or exchange1 with which each market town of any importance is provided4 ,in the hall each corn merchant in the district rents a small table or desk1 at which he stands during the hour of the market4 ,the farmer takes his sample from one merchant to another and sells it to the man who offers him the highest price4 ,the merchant keeps the sample and the farmer must deliver wheat of like quality4 ,in the western counties it is sometimes customary for the farmers to take their stand near their sample bags of corn whilst the merchants walk round and make their bids4 ,but unfortunately it too often happens that the struggling farmer cannot have a free hand in marketing his corn4 ,in many cases he must sell at once after harvest to raise the necessary cash to buy stock for the winter's feeding4 ,this causes a glut of wheat on the market in the early autumn1 and the price at once drops4 ,in other cases the farmer has bought on credit last winter's feeding stuffs1 or last spring's manures1 and is bound to sell his wheat to the merchant in whose debt he finds himself1 and to take the best price offered in a non-competitive market4 ,these are by no means all the handicaps of the farmer who would market his corn to the best advantage4 ,even the man who is blessed with plenty of ready money1 and can abide his own time for selling his wheat1 is hampered by the cumbrous weights and measures in use in this country1 and above all by their lack of uniformity4 ,in ,east ,anglia wheat is sold by the coomb of four bushels4 ,by common acceptance however the coomb has ceased to be four measured bushels1 and is always taken to mean #ah stones or #b cwt4 ,this custom is based on the fact that a bushel of wheat weighs on the average #fc pounds1 and four times #fc pounds makes #ah stones4 ,but this custom is quite local4 ,in other districts the unit of measure for the sale of wheat is the load1 which in ,yorkshire means three bushels1 in ,oxfordshire and ,gloucestershire #dj bushels1 and in parts of ,lancashire #add quarts4 ,another unit is the boll1 which varies from three bushels in the ,durham district to six bushels at ,berwick4 ,it will be noted that most of the common units are multiples of the bushel1 and it might be imagined that this would make their mutual relations easy to calculate4 ,this however is not so1 for in some cases it is still customary to regard a bushel as a measure of volume and to disregard the variation in weight4 ,in other cases the bushel1 as in ,east ,anglia1 means so many pounds1 but unfortunately not always the same number4 ,thus the ,east ,anglian bushel is #fc pounds1 the ,london bushel on ,mark ,lane ,market is the same1 the ,birmingham bushel is only #fb pounds1 the ,liverpool and ,manchester bushel #gj pounds1 the ,salop bushel #ge pounds1 and in ,south ,wales the bushel is #hj pounds4 ,finally1 wheat is sold in ,ireland by the barrel of #bhj pounds1 on ,mark ,lane by the quarter of eight bushels of #fc pounds1 imported wheat in ,liverpool and ,manchester by the cental of #ajj pounds1 and the official market returns issued by the ,board of ,agriculture are made in bushels of #fj pounds4 ,there is1 however1 a growing tendency to adopt throughout the country the #fc pound bushel or some multiple thereof1 for example the coomb or quarter1 as the general unit1 and the use of the old-fashioned measures is fast disappearing4 ,the farmer of course knows the weights and measures in use in his own and neighbouring markets1 but unless he takes the trouble to look up in a book of reference the unit by which wheat is sold at other markets1 and to make a calculation from that unit into the unit in which he is accustomed to sell1 the market quotations in the newspapers are of little use to him in enabling him to follow the fluctuations of the price of wheat4 ,thus a ,norfolk farmer who wishes to interpret the information that the price of the grade of wheat known as ,no4 #d ,manitoba on the ,liverpool market is #g_/c1 must first ascertain that wheat is sold at ,liverpool by the cental of #ajj pounds4 ,to convert the ,liverpool price into price per coomb1 the unit in which he is accustomed to sell1 he must multiply the price per cental by #beb1 the number of pounds in a coomb of wheat1 and divide the result by #ajj1 the number of pounds in a cental2 thus3 #g_/c x #beb #ajj #ah_/d4 ,it is evident that the farmer who wishes to follow wheat prices in order to catch the best market for his wheat1 must acquaint himself with an extremely complicated system of weights and measures1 and continually make troublesome calculations4 ,the average ,english farmer is an excellent craftsman4 ,he is unsurpassed1 indeed one may safely say unequalled1 as a cultivator of the land1 as a grower of crops1 and as a breeder and feeder of stock1 but like most people who lead open-air lives1 he is not addicted to spending his evenings in arithmetical calculations4 ,the corn merchant1 whose business it is to attend to such matters1 is therefore at a distinct advantage1 and the farmer loses the benefit of a rise in the market until the information slowly filters through to him4 ,no doubt the time will come1 when not only wheat selling1 but all business in this country1 will be simplified by the compulsory enactment of sale by uniform weight4 ,the change from the present haphazard system or want of system would no doubt cause considerable temporary dislocation of business1 and would abolish many ancient weights and measures1 interesting to the historian and the archaeologist in their relations to ancient customs1 but in the long run it could not but expedite business1 and remove one of the many handicaps attaching to the isolated position of the farmer4 ,having sold his wheat the farmer now puts it up in sacks of the standard of weight or measure prevailing in his district4 ,if the merchant who bought it happens to be also a miller1 as is frequently the case1 the wheat is delivered to the mill4 ,otherwise it is sent to the railway station to the order of the merchant who bought it4 ,meantime the merchant has probably sold it to a miller in a neighbouring large town1 to whom he directs the railway company to forward it4 ,thus the wheat directly or indirectly finds its way to a mill1 where it will be mixed with other wheats and ground into flour4 ,we have now followed wheat production in ,england from the ground to the mill4 ,but at the present time home grown wheat can provide only about one-fifth of the bread-stuffs consumed by the population of the ,united ,kingdom1 and any account of the growing of wheat cannot be complete without some mention of the methods employed in other countries4 ,the extensive methods of wheat-growing in the more thinly populated countries have already been shortly mentioned4 ,but though their methods of production are of the simplest1 the arrangements for marketing their produce are far more advanced in organisation than those already described for the marketing of home grown produce4 ,for thrashing in ,canada and the ,western ,states1 travelling machines are commonly used1 but they are larger than the machines in use in this country1 and the men who travel with them work harder and for longer hours4 ,it is usual for a ,canadian travelling 8outfit0 to thrash #ajjj bags of wheat in a day1 about ten times as much as is considered a day's thrashing in ,england4 ,harvesting and thrashing machinery has evolved to an extraordinary extent in the ,west on labour saving lines4 ,on the ,bonanza farms of the ,western ,states machines are in use which cut off the heads of the wheat1 thrash out the seed1 and bag it ready for delivery1 as they travel round and round the field4 ,such machines of course leave the straw standing where it grew1 and there it is subsequently burnt4 ,since wheat is grown every year1 few animals are kept beyond the working horses4 ,very little straw suffices for them and the rest has no value since its great bulk prohibits its profitable carriage to a distance4 ,after being thrashed the grain is delivered1 usually in very large loads drawn by large teams of horses1 to the nearest railway station1 whence it is despatched to the nearest centre where there is a grain store1 or elevator as it is called4 ,here it is sampled by inspectors under the control1 either of the ,government or the ,board of ,trade1 as the committee is called which manages the wheat exchange at ,chicago or other of the great wheat trading centres4 ,the inspectors examine the sample1 and on the result of their examination1 assign the wheat to one or other of a definite series of grades4 ,these grades are accurately defined by general agreement of the ,board of ,trade or by the ,government4 ,each delivery of wheat is kept separate for a certain number of days after it has been graded1 in case the owner wishes to appeal against the verdict of the inspector4 ,such appeals are allowed on the owner forfeiting one dollar per car load of grain if the verdict of the inspector is found to have been correct4 ,at the ,chicago wheat exchange #bg grades of wheat are recognised4 ,the following examples show the methods by which they are defined4 ,the definitions are the subject of frequent controversy4 ,no4 #a ,northern ,hard ,spring ,wheat shall be sound1 bright1 sweet1 clean1 and shall consist of over #ej per cent4 of hard ,scotch ,fife1 and weigh not less than #eh pounds to the measured bushel4 ,no4 #a ,northern ,spring ,wheat shall be sound1 sweet and clean2 may consist of hard and soft varieties of spring wheat1 but must contain a larger proportion of the hard varieties1 and weigh not less than #eg pounds to the measured bushel4 ,no4 #b ,northern ,spring ,wheat shall be spring wheat not clean enough or sound enough for ,no4 #a1 but of good milling quality1 and must not weigh less than #ef pounds to the measured bushel4 ,no4 #c ,northern ,spring ,wheat shall be composed of inferior shrunken spring wheat1 and weigh not less than #ed pounds to the measured bushel4 ,no4 #d ,northern ,spring ,wheat shall include all inferior spring wheat that is badly shrunken or damaged1 and shall weigh not less than #di pounds to the measured bushel4 ,when sampling wheat for grading1 the inspectors also estimate the number of pounds of impurities per bushel1 a deduction for which is made under the name of dockage4 ,at the same time the weight of wheat in each car is officially determined4 ,all these points1 grade1 dockage1 and weight1 are officially registered1 and as soon as the time has elapsed for dealing with any appeal which may arise1 the wheat is mixed with all the other wheats of the same grade which may be at the depot1 an official receipt for so many bushels of such and such a grade of wheat subject to so much dockage being given to the seller or his agent4 ,these official receipts are as good as cash1 and the farmer can realise cash on them at once by paying them into his bank1 without waiting for the wheat to be sold4 ,as each delivery of wheat is graded and weighed1 word is sent to the central wheat exchanges that so many bushels of such and such grades are at the elevator1 and official samples are also sent on at the same time4 ,the bulk of the sales however are made by grade and not by sample4 ,the actual buying and selling takes place in the wheat exchanges1 or wheat pits as they are called1 at ,chicago1 ,new ,york1 ,minneapolis1 ,duluth1 ,kansas ,city1 ,st ,louis1 and ,winnipeg1 each of which markets possesses its own special character4 ,chicago the greatest of the wheat markets of the world passes through its hands every year about #be million bushels of wheat1 chiefly from the western and south-western ,states4 ,it owes its preeminence to the converging railway lines from those ,states1 and to its proximity to ,lake ,michigan which puts it in touch with water carriage4 ,new ,york has grown in importance as a wheat market since the opening of the ,erie ,canal4 ,it is especially the market for export4 ,minneapolis is above all things a milling centre4 ,no doubt it has become so partly on account of the immense water-power provided by the ,falls of ,st ,antony4 ,it receives annually nearly #ajj million bushels of wheat1 its speciality being the various grades of hard spring wheat4 ,duluth is the most northern of the ,american wheat markets4 ,it receives and stores over #ej million bushels annually4 ,it owes its importance to its position on ,lake ,superior1 which is available for water carriage4 ,kansas ,city deals with over #dj million bushels per annum1 largely hard winter wheat1 which it ships down the ,missouri ,river4 ,st ,louis deals in soft winter wheats to the extent of about #bj million bushels per annum4 ,winnipeg is the market for ,canadian wheats1 to the extent of over #ej million bushels per annum4 ,it has the advantage of two navigable rivers1 the ,red ,river and the ,assiniboine1 and it is also a great railway centre4 ,its importance is increasing as the centre of the wheat-growing area moves to the north and west1 and it is rapidly taking the leading position in the wheat markets of the world4 ,it has been stated above that ,chicago is the greatest wheat market1 but it will no doubt have been noticed that this is not borne out by the figures which have been quoted4 ,for instance1 ,minneapolis receives every year nearly four times as much wheat as ,chicago4 ,the reason of this apparent discrepancy is that the sales at ,minneapolis are really bona fide sales of actual wheat for milling1 whilst nine-tenths of the sales at ,chicago are not sales of actual wheat1 but of what are known as 8futures40 ,on this assumption1 whilst the actual wheat received at ,chicago is #be million bushels1 the sales amount to #bej million bushels4 ,such dealing in futures takes place to a greater or less extent at all the great wheat markets1 but more at ,chicago than elsewhere4 ,the primary reason for dealing in futures is that the merchant who buys a large quantity of wheat1 which he intends to sell again at some future time1 may be able to insure himself against loss by a fall in price whilst he is holding the wheat he has bought4 ,this he does by selling to a speculative buyer an equal quantity of wheat to be delivered at some future time4 ,if whilst he is holding his wheat prices decline1 he will then be able to recoup his loss on the wheat by buying on the market at the reduced price now current to meet his contract with the speculative buyer1 and the profit he makes on this transaction will more or less cover his loss on the actual deal in wheat which he has in progress4 ,as a matter of fact he does not actually deliver the wheat sold to the speculative buyer4 ,the transaction is usually completed by the speculator paying to the merchant the difference in value between the price at which the wheat was sold and the price to which it has fallen in the interval4 ,this payment is insured by the speculative buyer depositing a margin of so many cents per bushel at the time when the transaction was made4 ,speculation is1 however1 kept within reasonable bounds by the fact that a seller may always be called upon to deliver wheat instead of paying differences4 ,the advantage claimed for this system of insurance is that whilst it is not more costly to the dealers in actual wheat than any other equally efficient method1 it supports a number of speculative buyers and sellers1 whose business it is to keep themselves in touch with every phase of the world's wheat supply4 ,the presence of such a body of men whose wits are trained by experience of market movements1 and who are ready at any moment to back their judgment by buying and selling large quantities of wheat for future delivery1 is considered to exert a steadying effect on the price of wheat1 and to lessen the extent of fluctuations in the price4 ,,chapter ,,iii ,,the ,,quality ,,of ,,wheat ,in discussing the quality of wheat it is necessary to adopt two distinct points of view1 that of the farmer and that of the miller4 ,a good wheat from the farmer's point1 of view is one that will year by year give him a good monetary return per acre4 ,now the monetary return obviously depends on two factors1 the yield per acre and the value per quarter1 coomb1 or bushel1 as the case may be4 ,these two factors are quite independent and must be discussed separately4 ,we will first confine our attention to the yield per acre4 ,this has already been shown to depend on the presence in the soil of plenty of the various elements required by plants1 in the case of wheat nitrogen being especially important4 ,the need of suitable soil and proper cultivation has also been emphasised4 ,these conditions are to a great extent under the control of the farmer1 whose fault it is if they are not efficiently arranged4 ,but there are other factors affecting the yield of wheat which cannot be controlled1 such for instance as sunshine and rainfall4 ,the variations in these conditions from year to year are little understood1 but they are now the subject of accurate study1 and already ,dr ,w4 ,n4 ,shaw1 the chief of the ,meteorological ,office has suggested a periodicity in the yield of wheat1 connected with certain climatic conditions1 notably the autumnal rainfall4 ,we have left to the last one of the most important factors which determine the yield of wheat1 namely1 the choice of the particular variety which is sown4 ,this is undoubtedly one of the most important points in wheat-growing which the farmer has to decide for himself4 ,the ,british farmer has no equal as a producer of high class stock4 ,he supplies pedigree animals of all kinds to the farmers of all other lands1 and he has attained this preeminence by careful attention to the great1 indeed the surpassing1 importance of purity of breed4 ,it is only in recent years that the idea has dawned on the agricultural community that breed is just as important in plants as in animals4 ,it is extraordinary that such an obvious fact should have been ignored for so long4 ,that it now occupies so prominently the attention of the farmers is due to the work of the agricultural colleges and experiment stations in ,sweden1 ,america1 and many other countries1 and last but by no means least in ,great ,britain4 ,this demonstration of the value of plant breeding is perhaps the greatest achievement in the domain of agricultural science since the publication of ,lawes and ,gilbert's classical papers on the manurial requirements of crops4 ,wheat is not only one of the most adaptable of plants4 ,it is also one of the most plastic and prone to variation4 ,during the many centuries over which its cultivation has extended it has yielded hundreds of different varieties1 whose origin1 however1 except in a few doubtful cases is unknown4 ,comparatively few of these varieties are in common use in this country1 and even of these it was impossible until recently to say which was the best4 ,it was even almost impossible to obtain a pure stock of many of the standard varieties4 ,this is by no means the simple matter it appears to be4 ,it is of course quite easy to pick out a single ear1 to rub out the grain from it1 to sow the grain on a small plot by itself and to raise a pound or so of perfectly pure seed4 ,this can again be sown by itself1 and the produce1 thrashed by hand1 will give perhaps a bushel of seed which will be quite pure4 ,from this seed it will be possible to sow something like an acre2 and now the trouble begins4 ,any kind of hand thrashing is extremely tedious for the produce of acre plots1 and thrashing by machinery becomes imperative4 ,now a thrashing machine is an extremely complicated piece of apparatus1 which it is practically impossible thoroughly to clean4 ,when once seed has been through such a machine it is impossible to guarantee its purity4 ,contamination in the thrashing machine is usually the cause of the impurity of the stocks of wheat and other cereals throughout the country4 ,the only remedy is for the farmer to renew his stock from time to time from one or other of the seedsmen or institutions who make it their business to keep on hand pure stocks obtained by the method above described4 ,illustration3 ,fig4 #a4 ,typical ears of a few of the many cultivated varieties of wheat ,comparative trials of pure stocks of many of the standard varieties of wheat1 and of the other cereals1 are being carried out in almost every county by members of the staff of the agricultural colleges4 ,the object of such trials is to determine the relative cropping power of the different varieties4 ,this might at first sight appear to be an extremely simple matter1 but a moment's consideration shows that this is not the case4 ,no soil is so uniform that an experimenter can guarantee that each of the varieties he is trying has the same chance of making a good yield as far as soil is concerned4 ,it is a matter of common knowledge too that every crop of wheat is more or less affected by insect and fungoid pests1 whose injuries are unlikely to fall equally on each of the varieties in any variety test4 ,many other causes of variation1 such as unequal distribution of manure1 inequalities in previous cropping of the land1 irregular damage by birds1 may well interfere with the reliability of such field tests4 ,much attention has been given to this subject during the last few years1 and it has been shown that as often as not two plots of the same variety of wheat grown in the same field under conditions which are made as uniform as possible will differ in yield by #e per cent4 or more4 ,obviously it is impossible to make comparisons of the cropping power of different varieties of wheat as the result of trials in which single plots of each variety are grown4 ,it is a deplorable fact however that the results of most of the trials which are published are based on single plots only of the varieties compared4 ,such results can have no claim to reliability4 ,single plots tests are excellent as local demonstrations1 to give the farmers a chance of seeing the general characters of the various wheats in the field1 but for the determination of cropping power their results are misleading4 ,for the comparison of two varieties however an accuracy of about #a per cent41 which is good enough for the purpose in view1 can be obtained by growing1 harvesting and weighing separately1 five separate plots of each variety under experiment1 provided the plots are distributed in pairs over the experimental field4 ,still greater accuracy can be attained by growing very large numbers of very small plots of each variety in a bird-proof enclosure4 ,the illustration shows such an enclosure at ,cambridge where five varieties were tested1 each on #dj plots4 ,each plot was one square yard1 and the whole #bjj plots occupied so small an area that uniformity of soil could be secured by hand culture4 ,several experimenters are now at work on these lines1 and it is to be hoped that all who wish to carry out variety tests will either follow suit1 or content themselves with using their single plots only for demonstrating the general characters of the varieties in the field4 ,so far we have confined our discussion to the standard varieties1 and we must now turn our attention to the work which has been done in recent years on the breeding of new varieties which will yield heavier crops than any of the varieties hitherto in cultivation4 ,illustration3 ,fig4 #b4 ,part of bird-proof enclosure containing many small plots for variety testing ,it is impossible to give more than a very brief outline of the vast amount of work which has been done on this subject4 ,broadly speaking1 two methods have been used1 selection and hybridisation4 ,of these selection is the simpler1 but even selection is by no means the simple matter it might appear to be4 ,let us examine for a moment the various characters of a single wheat plant which determine its capacity for yielding grain4 ,the average weight of one grain1 the number of grains in an ear1 the number of ears on the plant1 are obviously all of them characters which will influence the weight of grain yielded by the plant4 ,many experimenters have examined thousands of plants for these characters1 often by means of extremely ingenious mechanical sorting instruments1 and have raised strains of seed from the plants showing one or more of these characters in the highest degree4 ,the results of this method of selection have as a rule been unsuccessful1 no doubt because the size of the grain1 the number of grains in the ear1 and the number of ears on the plant1 are so largely determined by the food supply1 or by some other cause quite outside the plant itself4 ,they are in fact in most cases acquired characters1 and are not inherited4 ,this method of selection results in picking out rather the well nourished plant than the well bred one4 ,again it is obvious that the weight of grain per acre is measured by the weight of one grain1 multiplied by the number of grains per ear1 multiplied by the number of ears per plant1 multiplied by the number of plants per acre4 ,selecting for any one of these characters1 say large ears1 is quite likely to diminish other equally important characters1 say number of ears per plant4 ,in order to avoid these difficulties the method of selection according to progeny has been devised4 ,the essence of this method is to select for stock1 not the best individual plant1 but the plant whose progeny yields the greatest weight of seed per unit area4 ,this method was applied with great industry and some success in the ,minnesota wheat breeding experiments of ,willett ,hays4 ,large numbers of promising plants were collected from a plot of the best variety in that district4 ,the seed from each plant was rubbed out and sown separately4 ,one hundred seeds from each plant were sown on small separate plots which were carefully marked out and labelled4 ,every possible precaution was taken to make all the little plots uniform in every way4 ,by harvesting each plot separately1 and weighing the grain it produced1 it was possible to find out which of the original plants had given the largest yield4 ,this process was repeated by sowing again on separate plots a hundred seeds from each individual plant from the best plot1 and again weighing the produce of each plot4 ,after several repetitions it was stated that new strains were obtained which yielded considerably greater crops than the variety from which they were originally selected4 ,these results were published in #ahie1 but no definite statements have since appeared as to the success ultimately attained4 ,this method of selection is undoubtedly more likely to give successful results than the method which depends on the selection of plants for their apparent good qualities2 but it has several weak points4 ,in the first place it is almost impossible to make the soil of a large number of plots so uniform that variation in yield due to varying soil conditions will not mask the variations due to the different cropping power of the seed of the separate plants4 ,many experimenters are still at work with a view to overcome this difficulty4 ,secondly1 plant breeders are by no means agreed on the exact theoretical meaning of improvement by selection4 ,the balance of evidence at the present time seems to tend towards the general adoption of what is known as the pure-line theory4 ,according to this theory1 which was first enunciated by ,johannsen of ,copenhagen as the outcome of a lengthy series of experiments with beans1 the general population of plants1 in say a field of wheat of one of the standard varieties giving an average yield of say #dj bushels per acre1 consists of a very large number of races each varying in yielding capacity from say #cj to #ej bushels per acre4 ,these races can be separated by collecting a very large number of separate plants1 sowing say #ajj seeds from each on a separate plot1 and weighing the produce separately4 ,the crop on each plot1 being the produce of a separate plant1 will be a distinct race1 or pure line as it is called1 and each pure line will possess a definite yielding power of its own4 ,if this is so the difficulty of soil variation can be overcome by saving seed from many of the best plots1 and sowing it on several separate plots4 ,at harvest time these are gathered separately and weighed4 ,by averaging the weights of grain from many separate plots scattered over the experimental area the effect of soil variation can be eliminated4 ,the method is very laborious1 but seems to promise successful results4 ,for instance1 ,beaven of ,warminster1 working on these lines1 has succeeded in isolating a pure line of ,archer barley which is a distinct advance on the ordinary stocks of that variety4 ,there appears to be no reason why it should not be applied to wheat with equal success2 in fact1 ,percival of ,reading states that his selected ,blue ,cone wheat was produced in this way4 ,the essence1 of the method is that if the pure-line theory holds there is no necessity to continue selecting the best individual plant from each plot1 for each plot being the produce of a single plant must be a pure line with its own definite characters4 ,the whole of the seed from a number of the best plots can therefore be saved4 ,the seed from each of these good plots can be used to sow many separate plots3 by averaging the yields from these plots the effects of soil variation can be eliminated1 and the cropping power thus determined with great accuracy4 ,it is thus possible to pick out the best pure line with far greater certainty than in any other way4 ,it must not be forgotten1 however1 that the success of the method depends on the truth of the pure-line theory4 ,it should also be pointed out that the cereals are all self-fertilised plants4 ,when working on these lines with plants which are readily cross-fertilised1 such for instance as turnips or mangels1 it is necessary to enclose the original individual plants1 and the subsequent separate plots1 so as to prevent them from crossing with plants of other lines1 in which case the progeny would be cross-bred and not the progeny of a single plant4 ,this of course enormously increases the difficulty of carrying out the experiment4 ,enough has been said to show that the task of improving plants by systematic selection is an extremely tedious and difficult one4 ,of course anyone may be fortunate enough to drop on a valuable sport when carefully inspecting his crops1 and it appears likely that many of the most valuable varieties in cultivation have originated from lucky chances of this kind4 ,it has always been the dream of the plant breeder to make use of the process of hybridisation for creating new varieties1 but until the work of ,mendel threw new light on the subject the odds were against the success of the breeder4 ,the idea of the older hybridisers was that crossing two dissimilar varieties broke the type and gave rise to greatly increased variation4 ,from the very diverse progeny resulting from the cross1 likely individuals were picked out4 ,seed was saved from these and sown on separate plots1 and attempts were made to obtain a fixed type by destroying1 or roguing as it is called1 all the plants which departed from the desired type4 ,this was a tedious process which seldom resulted in success4 ,mendel's discoveries1 made originally nearly #ej years ago1 as the result of experiments in the garden of his monastery1 in the crossing of different varieties of garden peas1 remained unknown until rediscovered in #ahii4 ,in the #ab years which have elapsed since that date the results which have been achieved show clearly that the application of ,mendelian methods is likely greatly to increase the simplicity and the certainty of plant improvement by hybridisation4 ,illustration3 ,fig4 #c4 ,a wheat flower with the chaff opened to show the stamens and the stigmas ,perhaps the best way of describing the bearing of ,mendel's ,laws on the improvement of wheat is to give an illustration from the work carried out by ,biffen at ,cambridge1 dealing at first with simple characters obvious to anyone4 ,in one of his first experiments two varieties of wheat were crossed with each other4 ,the one variety possessed long loose beardless ears1 the other short dense bearded ears4 ,the crossing was performed early in ,june1 sometime before what the farmer calls flowering time4 ,the flowering of wheat as understood by the farmer is the escape of the stamens from the flower4 ,fertilisation always takes place before this1 and crossing must be done of course before self-fertilisation has been effected4 ,the actual crossing is done thus3 ,an ear of one of the varieties having been chosen1 one of the flowers is exposed by opening the chaff which encloses it 7,fig4 #c71 the stamens are removed by forceps1 and a stamen from a flower of the other variety is inserted1 care being taken that it bursts so that the pollen may touch the feathery stigmas4 ,the chaff is then pushed back so that it may protect the flower from injury4 ,the pollen grains grow on the stigmas1 and penetrate down the styles into the ovary4 ,in this way cross-fertilisation is effected4 ,it is usual to operate on several flowers on an ear in this way1 and to remove the other flowers1 so that no mistake may be made as to which seed is the result of the cross4 ,immediately after the operation the ear is usually tied up in a waxed paper bag4 ,this serves to make it absolutely certain that no other pollen can get access to the stigmas except that which was placed there4 ,at the same time it is a convenient way of marking the ear which was experimented upon4 ,the cross is usually made both ways1 each variety being used both as pollen parent and as ovary parent4 ,as soon as the cross-fertilised seeds are ripe they are gathered1 and early in the autumn they are sown4 ,it is almost necessary to sow them and other small quantities of seed wheat in an enclosure protected by wire netting4 ,otherwise they are very liable to suffer great damage from sparrows4 ,the plants which grow from the cross-fertilised seeds are known as the first generation4 ,in the case under consideration1 they were found to produce ears of medium length and denseness1 intermediate between the ears of the two parent varieties1 and to be beardless4 ,the first generation plants were also characterised by extraordinary vigour1 as is the case with almost all first crosses1 both in plants and animals4 ,their seed was saved and sown on a small plot1 and produced some hundreds of plants of the second generation4 ,on examining these second generation plants it was found that the characters of the parent varieties had rearranged themselves in every possible combination1 long ears with and without beard1 short ears with and without beard1 intermediate ears with and without beard1 as shown in ,fig4 #d4 ,these different types were sorted out and counted1 when they were found to be present in perfectly definite proportions4 ,this is best shown in the form of a tabulated statement1 thus3 ,ears ,ears ,ears ,ears ,ears ,ears ,long ,long ,medium ,medium ,short ,short ,beardless ,bearded ,beardless ,bearded ,beardless ,bearded #c #a #f #b #c #a ,translating this into words1 out of every #af plants in the second generation there were four long eared plants1 three beardless and one bearded2 eight plants with ears of intermediate length1 six beardless and two bearded2 and four short eared plants1 three beardless and one bearded4 ,the illustration shows all these types4 ,the experiment has been repeated several times and the same proportions were invariably obtained4 ,the result1 too1 was independent of the way the cross was made4 ,seed was collected separately from large numbers of single plants of each type4 ,the seed from each plant was sown by itself in a row1 so that its progeny could be separately observed4 ,it was found that all the plants of the second generation possessing ears of intermediate length produced in the third generation plants with long ears1 short ears1 and medium ears in the proportion of #a 3 #a 3 #b1 the same proportion in fact as in the second generation4 ,short eared plants produced only short eared offspring1 long eared plants only long eared offspring4 ,bearded plants produced only bearded offspring4 ,beardless plants1 however1 produced in some cases only beardless offspring1 in other cases both beardless and bearded offspring in the proportion of three of the former to one of the latter4 ,out of every three beardless plants only one was found to breed true1 whilst two gave a mixed progeny4 ,it appears therefore that in the second generation some of the types which occur breed true1 whilst others do not4 ,some of the true breeding individuals can be picked out at sight1 for instance1 those with long or short bearded ears4 ,some of those which will not breed true can also be recognised by inspection1 for instance1 all the plants with ears of intermediate length4 ,in other cases it is only possible to pick out the individual plants which breed true by growing their seed and observing how it behaves4 ,if it produces progeny all of which are like the plant from which the seed was obtained1 that plant is a fixed type and will breed true continuously in the future4 ,the final result of the experiment was to obtain in three years from the time the cross was made1 four fixed types which subsequent experience has shown breed true continuously1 a long eared bearded type1 a short eared beardless type1 a long eared beardless type and a short eared bearded type4 ,of these the second two are exactly like the two parental varieties1 but the first two are new1 each combining one character from each parent4 ,these fixed types already existed in the second generation4 ,mendel's discoveries with peas showed how to pick them out4 ,obviously there is no need for the years of roguing by which the older hybridisers used to attempt to fix their desired type4 ,all the types are present in the second generation4 ,mendel has shown how the fixed ones may be picked out4 ,illustration3 ,fig4 #d4 ,p1 ,p1 the two parental types4 ,f the first cross4 ,f1 #a-f1 the types found in the second generation ,the characters described above are not of any great economic importance4 ,biffen has shown that such important characters as baking strength and resistance to the disease known as yellow rust behave on crossing in the same way as beard4 ,working on the lines of the experiment described above he has succeeded in producing several new varieties which in baking strength and in rust resistance are a distinct advance on any varieties in cultivation in this country4 ,his method of working was to collect wheats from every part of the world1 to sow them and to pick out from the crop1 which was usually a mixed one1 all the pure types he could4 ,these were grown on small plots for several years under close observation4 ,many were found to be worthless and were soon discarded4 ,others were observed to possess some one valuable character4 ,amongst these a pure strain of ,red ,fife was obtained from ,canadian seed1 which was found to retain when grown in ,england the excellent baking strength of the hard wheats of ,canada and ,north ,america4 ,again1 other varieties were noticed to remain free from yellow rust year after year1 even when varieties on adjoining plots were so badly infected that they failed to produce seed4 ,other varieties1 too1 were preserved for the sturdiness of their straw1 their earliness in ripening1 vigour of growth1 or yielding capacity4 ,many crosses were made with these as parents4 ,the illustration shows a corner of the ,cambridge wheat-breeding enclosure including a miscellaneous collection of parent varieties4 ,the paper bags on the ears show where crosses have been made4 ,from the second generation numbers of individual plants possessing desirable characters were picked out1 and the fixed types isolated in the third generation by making cultures from the seed of these single plants4 ,the seed from these fixed types was sown on small field plots1 at which stage many had to be rejected because they were found wanting in some character of great practical importance which did not make itself evident in the breeding enclosure4 ,the illustration shows a case in point4 ,it was photographed after heavy rain in ,july4 ,the weakness of the straw of the variety on the left had not been noticed in the enclosure4 ,the types which approved themselves on the small field plots were again grown on larger plots so that their yield and milling and baking characters could be tested4 ,so far two types have survived the ordeal4 ,one combines the cropping power of the best ,english varieties with the baking strength of ,north ,american hard wheat4 ,it is the outcome of a cross between ,rough ,chaff and ,red ,fife4 ,its average crop in #aiaa was #ch bushels per acre as the result of #bh independent trials1 and1 where the local millers have found out its quality1 it makes on the market four or five shillings per quarter more than the ordinary ,english varieties4 ,the other resulted from a cross between ,square ,head's ,master and a rust-resisting type isolated from a graded ,russian wheat called ,ghirka4 ,it is practically rust-proof4 ,consequently it yields a heavier crop than any of the ordinary varieties which are all more or less susceptible to rust4 ,the presence of rust in and on the leaves hinders the growth of the plant1 lowers the yield1 and increases the proportion of shrivelled grains4 ,it has been estimated that rust diminishes the world's wheat crop by something like one third4 ,the new rust-proof variety gave an average yield of about #f bushels per acre more than ordinary varieties on the average of #bh trials last year4 ,it is called ,little ,joss and is especially valuable in the ,fens and other districts where rust is more than usually virulent4 ,illustration3 ,fig4 #e4 ,corner of bird-proof enclosure showing a varied assortment of parent varieties of wheat4 ,crosses have been made on some of them as shown by the ears tied up in paper bags ,illustration3 ,fig4 #f4 ,field plots of two new varieties of the same parentage which had approved themselves in the bird-proof enclosure4 ,that on the left had to be rejected on account of the weakness of its straw4 ,that on the right is the rust-proof variety known as ,little ,joss4 ,the photograph was taken after a storm which in the open field found out the weak point of the one variety ,,chapter ,,iv ,,the ,,quality ,,of ,,wheat ,,from ,,the ,,miller',s ,,point ,,of ,,view ,to the miller the quality of wheat depends on three chief factors1 the percentage of dirt1 weed seeds1 and other impurities1 the percentage of water in the sample1 and a complex and somewhat ill-defined character commonly called strength4 ,with the methods of growing1 cleaning and thrashing wheat practised in ,great ,britain1 practically clean samples are produced1 and home grown wheat is therefore on the whole fairly free from impurities4 ,this is1 however1 far from the case with foreign wheats1 many of which arrive at the ,english ports in an extremely dirty condition4 ,they are purchased by millers subject to a deduction from the price for impurities above the standard percentage which is allowed4 ,the purchase is usually made before the cargo is unloaded4 ,official samples are taken during the unloading in which the percentage of impurities is determined1 and the deduction1 if any1 estimated4 ,the percentage of water1 the natural moisture as it is usually called1 varies greatly in the wheats of different countries4 ,in home grown wheats it is usually #af per cent41 but in very dry seasons it may be much lower1 and in wet seasons it may rise to #ah per cent4 ,foreign wheats are usually considerably drier than home grown wheats4 ,in ,russian wheats #ab per cent4 is about the average1 and that too is about the figure for many of the wheats from ,canada1 the ,states1 ,argentina1 and parts of ,australia4 ,indian wheats sometimes contain less than #aj per cent4 ,this is also about the percentage in the wheats of the arid lands on the ,pacific coast and in ,australia4 ,these figures show that home grown wheats often contain as much as #e per cent4 more water than the foreign wheats imported from the more arid countries4 ,the more water a wheat contains the less flour it will yield in the mill4 ,consequently the less its value to the miller4 ,a difference of #e per cent4 of natural moisture means a difference in price of from #as4 #f;d4 to #bs4 per quarter in favour of the drier foreign wheats4 ,this is one of the reasons why foreign wheats command a higher price than those grown in this country4 ,turning to the third factor which determines the quality of wheat from the miller's point of view1 we may for the present define strength as the capacity for making bread which suits the public taste of the present day4 ,we shall discuss this point more fully when we deal with the baking of bread4 ,at present the only generally accepted method of determining the strength of a sample of wheat is to mill it and bake it1 usually into cottage loaves4 ,the strength of the wheat is then determined from their size1 shape1 texture1 and general appearance4 ,a really strong flour makes a large1 well risen loaf of uniformly porous texture4 ,wheats lacking in strength are known as weak4 ,a weak wheat makes a small flat loaf4 ,in order to give a numerical expression to the varying degrees of strength met with in different wheats1 the ,home ,grown ,wheat ,committee of the ,national ,association of ,british and ,irish ,millers have adopted a scale as the result of many thousand milling and baking tests4 ,on their scale the strength of the best wheat imported from ,canada1 graded as ,no4 #a ,manitoban1 or from the ,states graded as ,no4 #a ,hard ,spring1 is taken as #ajj1 that of the well-known grade of flour known as ,london ,households as #hj1 and that of the ordinary varieties of home grown wheat1 such as ,square ,head's ,master1 ,browick1 ,stand ,up1 etc41 as #fe4 ,the strength of most foreign wheats falls within these limits4 ,thus the strength of ,ghirka wheat from ,russia is about #he1 of ,choice ,white ,karachi from ,india #ge1 of ,plate ,river wheat from the ,argentine #hj1 etc4 ,the strongest of all wheats is grown in certain districts in ,hungary4 ,it is marked above #ajj on the scale1 but it is not used for bread making4 ,the soft wheats from the more arid regions in ,australia and the ,states are usually weaker than average home grown samples1 and are marked at #fj4 ,rivet or cone wheat1 a heavy cropping bearded variety much grown by small holders1--since the sparrow1 which would ruin small plots of any other variety1 seems to dislike ,rivet1 possibly on account of its beard1--is the weakest of all wheats1 and is only marked at #bj1 which means that bread baked from ,rivet flour alone would be practically unsaleable4 ,rivet wheat finds a ready sale1 however1 for making certain kinds of biscuits4 ,illustration3 ,fig4 #g4 ,loaves made from ,no4 #a ,manitoba4 ,strength #ajj ,illustration3 ,fig4 #h4 ,loaves made from average ,english wheat4 ,strength #fe ,illustration3 ,fig4 #i4 ,loaves made from ,rivet wheat4 ,strength #bj ,in order to make flour which will bake bread to suit the taste of the general public of the present day1 the miller finds it necessary to include in the mixture or blend of wheats which he grinds a certain proportion of strong wheats such as ,canadian1 ,american1 or ,russian4 ,the quantity of strong wheat available is limited4 ,consequently strong wheat commands a relatively high price4 ,the average difference in price of say ,no4 #a ,manitoban and home grown wheat is about #es4 per quarter4 ,it is possible of course that the public taste in bread may change1 and damp close textured bread may become fashionable4 ,in this case no doubt the difference in price would disappear4 ,under present conditions the necessity of including in his grinding mixture a considerable proportion of strong foreign wheat is a distinct handicap against the inland miller as compared with the port miller4 ,the latter gets his foreign wheat direct from the ship in which it is imported1 whilst the former has to pay railway carriage from the port to his mill4 ,the question naturally arises--is it not possible to grow strong wheats at home and sell them to the inland miller8 ,this question has been definitely answered by the work of the ,home ,grown ,wheat ,committee during the last #ab years4 ,the committee collected strong wheats from every country where they are produced1 and grew them in ,england4 ,from the first crop they picked out single plants of every type represented in the mixed produce1 for strong wheats as imported are usually grades and not pure varieties4 ,from the single plants they have established pure strains of which they have grown enough to mill and bake4 ,from most of the strong wheats they were unable to find any strain which would produce strong wheat in ,england4 ,thus the strong wheat of ,hungary when grown in ,england was no stronger than any of the ordinary typical home grown wheats4 ,but from the strong wheat of ,canada was isolated the variety known as ,red ,fife1 which makes up a very large proportion of the higher grades of ,american and ,canadian wheats1 and this variety when grown in ,england was found to continue to produce wheat as strong as the best ,canadian4 ,year after year it has been grown here1 and when milled and baked its strength has been found to be #ajj or thereabouts on the scale above described4 ,finally it was found that a strain of ,red ,fife which had been brought over from ,canada #bj years ago1 and grown continuously in the western counties ever since1 under the name of ,cook's ,wonder1 was still producing wheat which when ground and baked possessed a strength of about #ajj4 ,thus it was conclusively proved that in the case of ,red ,fife at any rate the ,english climate was capable of producing really strong wheat4 ,the strength of ,hungarian and ,russian wheats appear to be dependent on the climate of those countries4 ,red ,fife1 however1 produces strong wheat wherever it is grown4 ,it is interesting to note that this variety although first exploited in ,canada and the ,states is really of ,european origin4 ,it was taken out to ,canada by an enterprising ,scotchman called ,fife in a mixed sample of ,dantzig wheat4 ,he grew it for some time and distributed the seed4 ,pure strains have from time to time been selected by the ,american and ,canadian experiment stations4 ,but the discovery that ,red ,fife would produce strong wheat in ,england by no means solved the problem1 for when the ,home ,grown ,wheat ,committee distributed seed of their pure strain of that variety for extended testing throughout the country1 it was soon found to be only a poor yielder except in a few districts4 ,a yield of three quarters of strong grain1 even if it makes #djs4 per quarter on the market1 only gives to the farmer a return of #f per acre1 as compared with a return of nearly #h from #d quarters of weak grain worth #ces4 per quarter1 which can usually be obtained by growing ,square ,head's ,master1 or some other standard variety4 ,illustration3 ,fig4 #aj4 ,the left-hand loaf was made from average ,english wheat4 ,the loaf in the centre was made from ,burgoyne's ,fife1 and is practically identical in size and shape with the right-hand loaf which was made from imported ,no4 #a ,manitoba ,it was at this point that ,mendel's discoveries came to the rescue4 ,working on the ,mendelian lines already explained1 ,biffen at ,cambridge crossed ,red ,fife with many of the best ,english varieties4 ,from one of the crosses he was able to isolate a new variety in which are combined the strength of ,red ,fife and the vigour and cropping power of the ,english parent4 ,this variety1 known as ,burgoyne's ,fife1 has been grown and distributed by members of the ,millers' ,association4 ,in #aiaa on the average of #bh separate trials it yielded #ch bushels per acre1 which is well above the average of the best ,english varieties4 ,it has been repeatedly milled and baked1 and its strength is between #ij and #ajj1 practically the same as that of ,red ,fife4 ,it has been awarded many prizes at agricultural shows for quality1 and it commands on markets where the local millers have found out its baking qualities about the same price as the best foreign strong wheats1 that is to say from #ds4 to #es4 per quarter more than the average price of home grown wheat4 ,taking a fair average yield of wheat as four quarters per acre1 ,burgoyne's ,fife gives to the farmer an increased return over the ordinary varieties of about #afs4 per acre4 ,the introduction of such a variety makes the production of strong wheat in ,england a practicable reality1 and will be a boon both to the farmer and to the inland miller4 ,it is likely too that the possibility of obtaining a better return per acre will induce farmers to grow more wheat4 ,anything that tends to increase the production of home grown wheat and makes ,great ,britain less dependent on foreign supplies is a national asset of the greatest value4 ,it is of the greatest importance to the miller that he should be able to determine the strength of the wheats he buys4 ,obviously the method mentioned above1 which entails milling enough of the sample to enable him to bake a batch of bread1 is far too lengthy to be of use in assessing the value of a sample with a view to purchase4 ,the common practice is for the miller or corn merchant to buy on the reputation of the various grades of wheat1 which he confirms by inspection of the sample4 ,strength is usually associated with certain external characters which can readily be judged by the eye of the practised wheat buyer4 ,strong wheats are usually red in colour1 their skin is thin and brittle1 the grain is usually rather small1 and has a very characteristic horny almost translucent appearance4 ,the grains are extremely hard and brittle1 and when broken the inside looks flinty4 ,on chewing a few grains the starch is removed and there remains in the mouth a small pellet of gluten1 which is tough and elastic like rubber1 but not sticky4 ,weak wheats as a rule possess none of these characters4 ,their colour may be either red or white1 their skin is commonly thick and tough1 the grain is usually large and plump1 and often has an opaque mealy appearance4 ,it is soft and breaks easily1 and the inside is white1 soft and mealy4 ,very little gluten can be separated from it by chewing1 and that little is much less tough and elastic than the gluten of a strong wheat4 ,these characters1 however1 are on the whole less reliable than the reputation of the grade of wheat under consideration4 ,to make a reliable estimate of strength from inspection of a sample of wheat requires a natural gift cultivated by continual practice4 ,even the best commercial judges of wheat have been known to be deceived by a sample of white wheat which subsequent milling and baking tests showed to possess the highest strength4 ,the mistake was no doubt due to the great rarity of strength among white wheats4 ,this rarity will doubtless soon disappear now that a pure strain of ,white ,fife has been isolated and shown to possess strength quite equal to that of ,red ,fife4 ,sometimes too the ordinary home grown varieties produce most deceptive samples which show all the external characters of strong wheats4 ,such samples1 however1 on milling and baking are invariably found to possess the usual strength of home grown wheat1 about #fe on the scale4 ,these considerations show the great need of a scientific method of measuring strength1 which can be carried out rapidly and on a small sample of grain4 ,this need is felt at the present time not only by the miller and the merchant1 but by the wheat breeder4 ,for instance1 in picking out the plants possessing strong grain from cultures of the second generation after making his crosses1 the plant breeder up to the present has had to rely on inspection by eye1 and on the separation of gluten by chewing1 for a single plant obviously cannot yield enough grain to mill and bake4 ,this fact no doubt explains the differences of opinion among plant breeders on the inheritance of strength1 for it is not every one who can acquire the power of judging wheat accurately by his senses4 ,such a faculty is a personal gift1 and is at best apt to fail at times4 ,the search for a rapid and accurate method of measuring strength has for many years attracted the attention of investigators4 ,as might be expected most of the investigations have centred round the gluten1 for as mentioned above the gluten of a strong wheat is much more tough and elastic than that of a weak wheat4 ,gluten is a characteristic constituent of all wheats1 and it is the presence of gluten which gives to wheat flour the power of making bread4 ,the other cereals1 barley1 oats1 maize and rice are very similar to wheat in their general chemical composition1 but they do not contain gluten4 ,consequently they cannot make bread4 ,in making bread flour is mixed with water and yeast4 ,the yeast feeds on the small quantity of sugar contained in the flour1 fermenting it and forming from it alcohol and carbon dioxide gas4 ,the gluten being coherent and tough is blown into numberless small bubbles by the gas1 which is thus retained inside the bread4 ,on baking1 the high temperature of the oven fixes these bubbles by drying and hardening their walls1 and the bread is thus endowed with its characteristic porous structure4 ,if a cereal meal devoid of gluten is mixed with water and yeast1 fermentation will take place with formation of gas1 but the gas will escape at once1 and the product will be solid and not porous4 ,evidently from the baking point of view gluten is of the greatest importance4 ,one of the most obvious methods that have been suggested for estimating the strength of wheat depends on the estimation of the percentage of gluten contained in the flour4 ,the method has not turned out very successfully1 for strength seems to depend rather on the quality than on the quantity of gluten in the wheat4 ,much attention has been given to the study of the causes of the varying quality of the gluten of different wheats4 ,gluten for instance has been shown to be a mixture of two substances1 gliadin and glutenin1 and the suggestion has been made that its varying properties are dependent on the varying proportions of these two substances present in different samples4 ,this suggestion however failed to solve the problem4 ,after seven years of investigation the author has worked out the following theory of the strength of wheat flours1 which has finally enabled him to devise a method which promises to be both accurate and rapid1 and to require so little flour that it can readily be used by the wheat breeder to determine the strength of the grain in a single ear4 ,it has already been mentioned that a strong wheat is one that will make a large loaf of good shape and texture4 ,the strength of a wheat may therefore be defined as the power of making a large loaf of good shape and texture4 ,evidently strength is a complex of at least two factors1 size and shape1 which are likely to be quite independent of each other4 ,not infrequently1 for instance1 wheats are met with which make large loaves of bad shape1 or on the other hand1 small loaves of good shape4 ,probably therefore the size of the loaf depends on one factor1 the shape on another2 and the failure of the many attempts to devise a method of estimating strength have been caused by the impossibility of measuring the product of two independent factors by one measurement4 ,it seemed a feasible idea that the size of the loaf might depend on the volume of gas formed when yeast was mixed with different flours4 ,on mixing different flours with water and yeast it was found that for the first two or three hours they all gave off gas at about the same rate4 ,the reason of this is that all flours contain about the same amount of sugar1 approximately one per cent41 so that at the beginning of the bread fermentation all flours provide the yeast with about the same amount of sugar for food4 ,but this small amount of sugar is soon exhausted1 and for its subsequent growth the yeast is dependent on the transformation of some of the starch of the flour into sugar4 ,wheat like many other seeds contains a ferment or enzyme called diastase1 which has the power of changing starch into sugar1 and the activity of this ferment varies greatly in different wheats4 ,the more active the ferment in a flour the more rapid the formation of sugar4 ,consequently the more rapidly the yeast will grow1 and the greater will be the volume of gas produced in the later stages of fermentation in the dough4 ,as a rule it is not practicable to get the dough moulded into loaves and put into the oven before it has been fermenting for about six or eight hours4 ,if the flour possesses an active ferment it will still be rapidly forming gas at the end of this time1 and the loaf will go into the oven distended with gas under pressure from the elasticity of the gluten which forms the walls of the bubbles4 ,the heat of the oven will cause each gas bubble to expand1 and a large loaf will be the result4 ,if the ferment of the flour is of low activity it will not be able to keep the yeast supplied with all the sugar it needs1 the volume of gas formed in the later stages of the fermentation of the dough will be small1 the dough will go into the oven without any pressure of gas inside it1 little expansion will take place as the temperature rises1 and a small loaf will be produced4 ,from these facts it is quite easy to devise a method of estimating how large a loaf any given flour will produce4 ,the following method is that used by the author4 ,a small quantity of the flour1 usually #bj grams1 is weighed out and put into a wide mouthed bottle4 ,a flask of water is warmed to #dj ,c41 of this #ajj c4c4 is measured out1 and into it #b grams of compressed yeast is intimately mixed1 #bj c4c4 of the mixture being added to the #bj grams of flour in the bottle4 ,the flour and yeast-water are then mixed into a cream by stirring with a glass rod4 ,the bottle is then placed in a vessel of water which is kept by a small flame at #ce ,c4 ,the bottle is connected to an apparatus for measuring gas1 and the volume of gas given off every hour is recorded4 ,as already mentioned all flours give off about the same volume of gas during the first three hours4 ,after this length of time the volume of gas given off per hour varies greatly with different flours4 ,thus a flour which will bake a large loaf gives off under the conditions above described about #bj c4c4 of gas during the sixth hour of fermentation1 whilst a flour which bakes a small tight loaf gives off during the sixth hour of fermentation only about #e c4c4 of gas4 ,having devised a feasible method of estimating how large a loaf any given flour will make1 the problem of the shape and texture still remains4 ,previous investigators had exhausted almost every possible chemical property of gluten in their search for a method of estimating strength4 ,the author therefore determined to study its physical properties4 ,now gluten is what is known as a colloid substance1 like albumen the chief constituent of white of egg1 casein the substance which separates when milk is curdled1 or clay which is a well known constituent of heavy soils4 ,such colloid substances can scarcely be said to possess definite physical properties of their own1 for their properties vary so largely with their surroundings4 ,the white of a fresh egg is a thick glairy liquid4 ,on heating it becomes a white opaque solid1 and the addition of certain acids produces a similar change in its properties4 ,casein exists in fresh milk in solution4 ,the addition of a few drops of acid causes it to separate as finely divided curd4 ,if1 however1 the milk is warmed before the acid is added the casein separates as a sticky coherent mass4 ,every farmer knows that lime improves the texture of soils containing much clay1 because the lime causes the clay to lose its sticky cohesive nature4 ,such instances show that the properties of colloid substances are profoundly modified by the presence of chemical substances4 ,wheat1 like almost all plant substances1 is slightly acid1 and the degree of acidity varies in different samples4 ,accordingly the effect of acids on the physical properties of gluten was investigated1 and it was found that by placing bits of gluten in pure water and in acid of varying concentration it could be made to assume any consistency from a state of division so fine that the separate particles could not be seen1 except by noticing that their presence made the water milky1 to a tough coherent mass almost like indiarubber 7,fig4 #aa74 ,it was found1 however1 that the concentration of acid in the wheat grain was never great enough to make the gluten really coherent4 ,illustration3 ,fig4 #aa4 ,gluten in pure water2 soft1 but tough and elastic ,gluten in very weak hydrochloric acid 7#c parts in #ajj1jjj of water72 it floats about in powder1 having entirely lost cohesion1 and makes the water milky ,gluten in hydrochloric acid 7#c parts in #ajjj of water72 very hard and tough ,but wheat contains also varying proportions of such salts as chlorides1 sulphates and phosphates1 which are soluble in water1 and the action of such salts on gluten was next tried4 ,it was at once found that these salts in the same concentration as they exist in the wheat grain were capable of making gluten coherent1 but that the kind of coherence produced was peculiar to each salt4 ,phosphates produce a tough and elastic gluten such as is found in the strongest wheats4 ,chlorides and sulphates on the other hand make gluten hard and brittle1 like the gluten of a very weak wheat 7,fig4 #ab74 ,the next step was to make chemical analyses to find out the amount of soluble salts in different wheats4 ,strong wheats of the ,fife class were found to contain not less than #a part of soluble phosphate in #ajjj parts of wheat1 whilst ,rivet wheat1 the weakest wheat that comes on the market1 contained only half that amount4 ,rivet1 however1 was found to be comparatively rich in soluble chlorides and sulphates1 which are present in very small amounts in strong wheats of the ,fife class4 ,ordinary ,english wheats resemble ,rivet1 but they contain rather more phosphate and rather less chlorides and sulphates4 ,after making a great many analyses it was found that the amount of soluble phosphate in a wheat was a very good index of the shape and texture of the loaf which it would make4 ,the toughness and elasticity of the gluten no doubt depend on the concentration of the soluble phosphate in the wheat grain1 the more the soluble phosphate the tougher and more elastic the gluten1 and a tough and elastic gluten holds the loaf in shape as it expands in the oven1 and prevents the small bubbles of gas running together into large holes and spoiling the texture4 ,illustration3 ,fig4 #ab4 ,gluten in water containing both acid and phosphate2 very tough and elastic ,gluten in water containing both acid and sulphates4 ,it shows varying degrees of coherence1 but is brittle or 8short0 ,these facts suggest at once a method for estimating the shape and texture of the loaf which can be made from any given sample of wheat4 ,an analysis showing the amount of soluble phosphate in the sample should give the desired information4 ,but unfortunately such an analysis is not an easy one to make1 and requires a considerable quantity of flour4 ,in making these analyses it was noticed that when the flours were shaken with water to dissolve the phosphate1 and the insoluble substance removed by filtering1 the solutions obtained were always more or less turbid1 and the degree of turbidity was found to be related to the amount of phosphate present and to the shape of loaf produced4 ,on further investigation it was found that the turbidity was due to the fact that the concentration of acid and salts which make gluten coherent1 also dissolve some of it1 and gluten like other colloids gives a turbid solution4 ,it was also found that the amount of gluten dissolved1 and consequently the degree of turbidity1 is related to the shape of the loaf which the flour will produce4 ,now it is quite easy to measure the degree of turbidity of a solution by pouring the solution into a glass vessel below which a small electric lamp is placed1 and noting the depth of the liquid through which the filament of the lamp can just be seen4 ,the turbidities were1 however1 so slight that it was found necessary to increase them by adding a little iodine solution which gives a brown milkiness with solutions of gluten1 the degree of milkiness depending on the amount of gluten in the solution4 ,in this way a method was devised which is rapid1 easy1 and can be carried out with so little wheat that the produce of one ear is amply sufficient4 ,it can therefore be used by the plant breeder for picking out from the progeny of his crosses those individual plants which are likely to give shapely loaves4 ,the method is as follows3 ,an ear of wheat is rubbed out and ground to powder in a small mill4 ,one gram of this powder1 or of flour if that is to be tested1 is weighed out and put into a small bottle4 ,to it is added #bj c4c4 of water4 ,the bottle is then shaken for one hour4 ,at the end of this time the contents are poured onto a filter4 ,to #ae c4c4 of the solution #a c4c4 of a weak solution of iodine is added1 and after standing for half an hour the turbidity test is applied4 ,working in this way it is possible to see through only #aj c4m4 of the solution thus obtained from such a wheat as ,red ,fife1 as compared with #be c4m4 in the case of ,rivet4 ,other wheats yield solutions of intermediate opacity4 ,this method is now being tested in connection with the ,cambridge wheat breeding experiments4 ,,chapter ,v ,,the ,,milling ,,of ,,wheat ,in order that wheat may be made into bread it is necessary that it should be reduced to powder4 ,in prehistoric times this was effected by grinding the grain between stones4 ,two stones were commonly used1 the lower one being more or less hollowed on its upper surface so as to hold the grain while it was rubbed by the upper one4 ,as man became more expert in providing for his wants1 the lower stone was artificially hollowed1 and the upper one shaped to fit it1 until in process of time the two stones assumed the form of a primitive mortar and pestle4 ,the next step in the evolution of the mill was to make a hole or groove in the side of the lower stone through which the powdered wheat could pass as it was ground4 ,this device avoided the trouble of emptying the primitive mill1 and materially saved the labour of the grinder4 ,such mills are still in use in the less civilised countries in the ,east1 and are of course worked by hand as in primitive times4 ,they gradually developed as civilization progressed into the stone mills which ground all the breadstuffs of the civilised world until about #dj years ago4 ,the old fashioned stone mill was1 and indeed still is1 a weapon of the greatest precision4 ,it consists of a pair of stones about four feet in diameter1 the lower of which is fixed whilst the upper is made to revolve by mechanical power at a high speed4 ,each stone is made of a large number of pieces of a special kind of hard stone obtained from ,france4 ,these pieces are cemented together1 and the surfaces which come into contact are patiently chipped until they fit one another to a nicety all over4 ,the surface of the lower stone is then grooved so as to lead the flour to escape from between the stones at definite places where it is received for further treatment4 ,the grain to be ground is fed between the stones through a hole at the centre of the upper stone4 ,it has been stated above that the surfaces of the two stones are in contact4 ,as a matter of fact this is not strictly true4 ,the upper stone is suspended so that the surfaces are separated by a small fraction of an inch1 and it will be realised at once that this suspension is a matter of the greatest delicacy4 ,to balance a stone weighing over half a ton so that1 when revolving at a high rate of speed1 it may be separated from its partner at no point over its entire surface of about #ab square feet by more than the thickness of the skin of a grain of wheat1 and yet may nowhere come into actual contact1 is an achievement of no mean order4 ,stone mills of this kind were usually driven by water power1 or in flat neighbourhoods by wind power1 though in some cases steam was used4 ,it was the common practice to subject the ground wheat from the stones to a process of sifting so as to remove the particles of husk from the flour4 ,the sifting was effected by shaking the ground wheat in a series of sieves of finely woven silk1 known as bolting cloth4 ,in this way it was possible to obtain a flour which would make a white bread4 ,the particles of husk removed by the sifting were sold to farmers for food for their animals1 under the name of bran1 sharps1 pollards1 or middlings1 local names for products of varying degrees of fineness1 which may be classed together under the general term wheat offals4 ,the ideal of the miller was to set his stones so that they would grind the flour to a fine powder without breaking up the husk more than was absolutely necessary4 ,when working satisfactorily a pair of stones were supposed to strip off the husk from the kernel4 ,the kernel should then be finely pulverised4 ,the husk should be flattened out between the stones1 which should rub off from the inside as completely as possible all adhering particles of kernel4 ,if this ideal were attained1 the mill would yield a large proportion of fairly white flour1 and a small proportion of husk or offals4 ,as long as home grown wheats were used this ideal could be more or less attained because the husk of these wheats is tough and the kernel soft4 ,comparatively little grinding suffices to reduce the kernel to the requisite degree of fineness1 and this the tough husk will stand without being itself unduly pulverised4 ,consequently the husk remains in fairly large pieces1 and can be separated by sifting1 with the result that a white flour can be produced4 ,but home grown wheat ceased to provide for the wants of the nation more than half a century ago4 ,already in #ahgj half the wheat ground into flour in the ,united ,kingdom was imported from abroad1 and this proportion has steadily increased1 until at the present time only about one-fifth of the wheat required is grown at home4 ,many of the wheats which are imported are harder in the kernel1 and thinner and more brittle in the husk1 than the home grown varieties4 ,consequently they require more grinding to reduce the kernel to the requisite degree of fineness1 and their thin brittle husk is not able to resist such treatment4 ,it is itself ground to powder along with the kernel1 and cannot be completely separated from the flour by sifting4 ,such wheats therefore1 when ground between stones1 yield flour which contains much finely divided husk1 and this lowers its digestibility and gives it a dark colour4 ,in the decades before #ahgj when the imports of foreign wheats first reached serious proportions1 and all milling was done by stones1 dark coloured flours were common1 and people would no doubt have accepted them without protest1 if no other flours had been available4 ,but as it happened millers in ,hungary1 where hard kernelled1 thin skinned wheats had long been commonly grown1 devised the roller milling process1 which produces fine white flour from such wheats1 no matter how hard their kernels or how thin their skins4 ,the idea of grinding wheat between rollers was at once taken up in ,america and found to give excellent results with the hard thin skinned wheats of the north-west4 ,the fine white flours thus produced were sent to ,england1 and at once ousted from the home markets the dark coloured flours produced from imported wheats in the ,english stone mills4 ,the demand for the white well-risen bread produced from these roller milled imported flours showed at once that the public preferred such bread to the darker coloured heavier bread yielded by stone-ground flours1 especially those made from the thin skinned foreign wheats4 ,this state of things was serious both for the millers and the farmers4 ,the importation of flour instead of wheat must obviously ruin the milling industry1 and since wheat offals form no inconsiderable item in the list of feeding stuffs available for stock keepers1 a decline of the milling industry restricts the supply of food for his stock1 and thus indirectly affects the farmer4 ,at the same time the preference shown by the public for bread made from fine white imported flour1 to some extent depreciated the value of home grown wheat4 ,it was by economic conditions of this kind that the millers were compelled in the early seventies to alter their methods4 ,the large firms subscribed more capital and installed roller plant in their mills4 ,these at once proved a success and the other firms have followed suit4 ,at the present time considerably more than #ij per cent4 of the flour used in this country is the product of roller mills4 ,the keen competition which has arisen in the milling industry during the last #ce years has produced great improvements in roller plant1 and the methods of separation now in use yield flours which in the opinion of the miller1 and apparently too in the opinion of the general public1 are far in advance of the flours which were produced in the days of stone milling4 ,perhaps the first impression which a visitor to a modern roller mill would receive is the great extent to which mechanical contrivances have replaced hand labour4 ,once the wheat has been delivered at the mill it is not moved again by hand until it goes away as flour and offals4 ,it is carried along by rapidly moving belts1 elevated by endless chains carrying buckets1 allowed to fall again by gravity1 or perhaps in other cases transported by air currents4 ,another very striking development is the great care expended in cleaning the grain before it is ground4 ,this cleaning is the first process to which the wheat is subjected4 ,it is especially necessary in the case of some of the foreign wheats which arrive in this country in a very dirty condition4 ,the impurities consist of earth1 weed seeds1 bits of husk and straw2 iron nails1 and other equally unlikely objects are by no means uncommon4 ,some of these are removed by screens1 but besides screening the wheat is actually subjected to the process of washing with water4 ,for this purpose it is elevated to an upper floor of the mill1 and allowed to fall downwards through a tall vessel through which a stream of water is made to flow4 ,as it passes through the water it is scrubbed by a series of mechanically driven brushes to remove the earthy matter which adheres to the grain4 ,this is carried away by the stream of water4 ,after cleaning the grain next undergoes the process of conditioning4 ,the object of this process is so to adjust the moisture of the grain that the husk may attain its maximum toughness compatible with a reasonable degree of brittleness of kernel1 the idea being to powder the kernel with the minimum of grinding and without unduly powdering the husk4 ,by attention to this process separation of flour and husk is made easier and more complete4 ,the essential points in the process are to moisten the grain1 either in the course of cleaning as above described1 or if washing is not necessary1 by direct addition of water4 ,the moisture is given some time to be absorbed into the grain1 which is then dried until the moisture content falls to what experience shows to be the most successful figure for the wheat in question4 ,illustration3 ,fig4 #ac4 ,first break rolls seen from one end4 ,the ribs can just be seen where the two rolls touch ,cleaning and conditioning having been attended to1 the grain is now conveyed to the mill proper4 ,this of course is done by a mechanical arrangement which feeds the grain at any desired rate into the hopper which supplies the first pair of rolls4 ,these rolls consist of a pair of steel cylinders usually #aj inches in diameter and varying in length from #bj inches to #e feet according to the capacity of the mill4 ,the surfaces of the cylinders are fluted or ribbed1 the distance from rib to rib being about one-tenth of an inch4 ,the rollers are mounted so that the distance between their surfaces can be adjusted4 ,they are set so that they will break grains passing between them to from one-half to one-quarter their original size4 ,they are made to revolve so that the parts of the surfaces between which the grains are nipped are travelling in the same direction4 ,one roll revolves usually at about #cej revolutions per minute1 the other at rather less than half that rate 7,fig4 #ad74 ,it is obvious from the above description that a grain of wheat falling from the hopper on to the surface of the moving rollers will be crushed or nipped between them1 and that since the rollers are moving at different rates1 it will at the same time be more or less torn apart4 ,by altering the distance between the rollers and their respective speeds of revolution the relative amounts of nipping and tearing can be adjusted to suit varying conditions4 ,illustration3 ,fig4 #ad4 ,break rolls4 ,the large and small cog-wheels are the simplest device used to give the two rolls different speeds4 ,the larger cog-wheel is driven by power and drives the smaller1 of course at a much higher rate of revolution ,the passage of the grain through such a pair of rollers is known technically as a break4 ,its object is to break or tear open the grain with the least possible amount of friction between the grain and the grinding surfaces4 ,since the rollers are cylindrical it is obvious that the grain will only be nipped at one point of their surfaces1 and even here the friction is reduced as much as possible by making both the grinding surfaces move in the same direction4 ,as already explained it can be diminished1 if the condition of the wheat allows1 by diminishing the difference in speed between the two rolls4 ,the result of the first break is to tear open the grains4 ,at the same time a small amount of the kernel will be finely powdered4 ,the rest of the kernel and husk will still remain in comparatively large pieces4 ,the tearing open of the grain sets free the dirt which was lodged in the crack or furrow which extends from end to end of the grain4 ,this dirt cannot be removed by any method of cleaning4 ,it only escapes when the grain is torn open in the break4 ,it is generally finely divided dirt and cannot be separated from the flour formed in this process4 ,consequently the first break flour is often more or less dirty1 and the miller tries to adjust his first break rolls so that they will form as little flour as possible4 ,the first break rolls not only powder a little of the kernel1 but they also reduce to a more or less fine state of division a little of the husk4 ,the result of the passage of the grain through the first break rolls is to produce from it a mixture of a large quantity of comparatively coarse particles of kernel to many of which husk is still adherent1 a small quantity of finely divided flour which is more or less discoloured with dirt1 and a small quantity of finely divided husk4 ,this mixture1 which is technically known as stock1 is at once subjected to what is called separation1 with the object of separating the flour from the other constituents before it undergoes any further grinding4 ,it is one of the guiding principles of modern milling that the flour produced at each operation should be separated at once so as to reduce to a minimum the grinding which it has to undergo4 ,separation is brought about by the combination of two methods4 ,the stock is shaken in contact with a screen made of bolting silk so finely woven that it contains from #ej to #aej meshes to the inch1 according to the fineness of the flour which it is desired to separate4 ,the shaking is effected in several different ways4 ,sometimes the silk is stretched on a frame so as to make a kind of flat sieve4 ,this is shaken mechanically whilst the stock is allowed to trickle over its surface1 so that the finely divided particles of flour may fall through the meshes and be collected separately from the larger particles which remain on the top4 ,these larger particles are partly heavy bits of broken kernel and partly light bits of torn husk4 ,in order to separate them advantage is taken of the fact that a current of wind can be so adjusted that it will blow away the light and fluffy husk particles without disturbing the heavy bits of kernel4 ,by means of a mechanically driven fan a current of air is blown over the surface of the sieve1 in the direction opposite to that in which the stock is travelling4 ,as the stock rolls over and over in its passage from the upper to the lower end of the inclined sieve the fluffy particles of husk are picked up by the air current and carried back to the top of the sieve where they fall1 as the current slackens1 into a receptacle placed to receive them4 ,thus by the combination of sifting and air carriage the stock is separated into a small quantity of finished flour1 a small quantity of finished husk or offal1 and a large quantity of large particles of kernel with husk still adhering to some of them4 ,these large particles1 which are called semolina1 of course require further grinding4 ,different methods of sifting are often used in place of the one above described1 especially for completing the purification of the flour4 ,sometimes the silk is stretched round a more or less circular frame so as to form a long cylinder covered with silk4 ,the stock is delivered into the higher end of this cylinder which is made to revolve4 ,this causes the stock to work its way through the cylinder1 and during its progress the finely ground flour finds its way through the meshes1 and is separated as before from the coarser particles4 ,such a revolving sieve is known as a reel4 ,in a somewhat similar arrangement known as a centrifugal a series of beaters is made to revolve rapidly inside a stationary cylindrical sieve4 ,the stock is admitted at one end and is thrown by the revolving beaters against the silk cover4 ,the finer particles are driven through the meshes of the silk1 the coarser particles find their way out of the cylinder at the other end4 ,sometimes for separating very coarse particles wire sieves of #cj meshes1 or thereabouts1 to the inch are used4 ,whatever the method the object is to separate at once the finished flour and offal from the large particles of kernel which require further grinding4 ,illustration3 ,fig4 #ae4 ,a pair of reduction rolls4 ,they are smooth1 and the cog-wheels being nearly of the same size the speed of the two rolls is nearly equal ,these large particles1 semolina1 are next passed between one or more pairs of smooth rolls known as reduction rolls 7,fig4 #ae74 ,these are set rather nearer together than the break rolls1 and the difference in speed between each roll and its partner is quite small4 ,the object of reduction is to reduce the size of the large particles of semolina and to produce thereby finely divided flour4 ,the stock from the first pair or pairs of reduction rolls contains much finely ground flour mixed with coarser particles of kernel with or without adherent husk4 ,it is at once submitted to the separation and purification processes as above described4 ,this yields a large quantity of finished flour which is very white and free from husk4 ,it represents commercially the highest grade of flour separated in the mill and is described technically as patents4 ,a small amount of finished offal is also separated at this stage4 ,the coarse particles of kernel with adherent husk from which the flour and offal have been separated are now passed through a second pair of break rolls more finely fluted than before1 known as the second break4 ,these are set closer together than the first break rolls4 ,their object is to rub off more kernel from the husk4 ,the stock from them is again separated1 the flour and finished offal being removed as before4 ,the coarser particles are again reduced by smooth reduction rolls1 and a second large quantity of flour separated4 ,this is commercially high grade flour and is usually mixed with the patents already separated4 ,the coarse particles left after this separation are usually subjected to a third and a fourth break1 each of which is succeeded by one or two reductions4 ,separation of the stock and purification of the flour take place after each rolling1 so that as soon as any flour or husk is finely ground it may be at once separated without further grinding4 ,the last pair of fluted rolls1 the fourth break1 are set so closely together that they practically touch both sides of the pieces of husk which pass through them4 ,they are intended to scrape the last particles of kernel from the husk4 ,this is very severe treatment1 and usually results in the production of much finely powdered husk which goes through the sifting silk and cannot be separated from the flour4 ,the flour from the fourth break is therefore usually discoloured by the presence of much finely divided husk4 ,for this reason it ranks as of low commercial grade4 ,the later reductions too yield flours containing more or less husk1 which darkens their colour4 ,they are usually mixed together and sold as seconds4 ,the fate of the germ in the process of roller milling is a point of considerable interest1 both on account of the ingenious way in which it is removed1 and because of the mysterious nutritive properties which it is commonly assumed to possess4 ,the germ of a grain of wheat forms only about #a per cent4 by weight of the grain4 ,it differs in composition from the rest of the grain1 being far richer in protein1 fat1 and phosphorus4 ,its special feeding value can1 however1 scarcely be explained in terms of these ingredients1 for its total amount is so small that its presence or absence in the flour can make only a very slight difference in the percentages of these substances4 ,but this point will be discussed fully in a subsequent chapter4 ,here it is the presence of the fat which is chiefly of interest4 ,according to the millers the fat of the germ is prone to become rancid1 and to impart to the flour1 on keeping1 a peculiar taste and odour which affects its commercial value4 ,they have therefore devised with great ingenuity a simple method of removing it4 ,this method depends on the fact that the presence in the germ of so much fat prevents it from being ground to powder in its passage between the rolls4 ,instead of being ground it is pressed out into little flat discs which are far too large to pass with the flour through the sifting silks or wires1 and far too heavy to be blown away by the air currents which remove the offals4 ,the amount which is thus separated is usually about #a per cent4 of the grain so that one third of the total quantity of germ present in the grain is not removed as such4 ,considerable difficulties arise in attempting to trace this fraction1 and at present it is impossible to state with certainty what becomes of it4 ,the germ which is separated is sold by the ordinary miller to certain firms which manufacture what are known as germ flours4 ,it is subjected to a process of cooking which is said to prevent it from going rancid1 after which it is ground with wheat1 the product being patent germ flour4 ,,chapter ,,vi ,,baking ,in discussing the method of transforming flour into bread it will be convenient to begin by describing in detail one general method4 ,the modifications used for obtaining bread of different kinds1 and for dealing with flours of different qualities will be shortly discussed later when they can be more readily understood4 ,bread may be defined as the product of cooking or baking a mixture of flour1 water1 and salt1 which is made porous by the addition of yeast4 ,it is understood to contain no other substances than these--flour1 salt1 water and yeast4 ,in the ordinary process the first step is to weigh out the flour which it is proposed to bake4 ,this is then transferred to a vessel which in a commercial bakery is usually a large wooden trough1 in a private house an earthenware bowl4 ,the necessary amount of yeast is next weighed out and mixed with water4 ,nowadays compressed or ,german yeast is almost always used at the rate of #a to #b lbs4 per sack or #bhj lbs4 of flour4 ,for smaller quantities of flour relatively more yeast is needed1 for instance #b ozs4 per stone4 ,formerly brewers' yeast or barm was used1 but its use has practically ceased because it is difficult to obtain of standard strength4 ,some people who profess to be connoisseurs of bread still prefer it because as they say it gives a better flavour to the bread4 ,the water with which the yeast is mixed is warmed so as to make the yeast more active4 ,the flour is then heaped up at one end of the vessel in which the mixing is to take place1 and salt at the rate of #b to #e lbs4 per sack is thoroughly stirred into it4 ,a hollow is then made in the heap of flour into which the mixture of yeast and water is poured4 ,more warm water is added so that enough water in all may be present to convert all1 or nearly all1 the flour into dough of the required consistency4 ,when dealing with a flour with which he is familiar the baker knows by experience how much water he requires per sack4 ,in the case of an unaccustomed brand of flour he determines the amount by a preliminary trial with a small quantity 7,figs4 #af and #ag74 ,flour from the heap is then stirred into the water until the whole of the flour is converted into a stiff paste or dough as it is called4 ,by this method a little dry flour will always separate the dough from the sides of the vessel and this will prevent the dough from sticking to the vessel and the hands4 ,the dough is then thoroughly worked or kneaded so as to ensure the intimate mixture of the ingredients4 ,the vessel is then covered to keep the dough warm4 ,in private houses this is ensured by placing the vessel near the fire4 ,in bakeries the room in which the mixing is conducted is usually kept at a suitable temperature4 ,the yeast cells which are thoroughly incorporated in the dough1 find themselves in possession of all they require to enable them to grow4 ,the presence of water keeps them moist1 and dissolves from the flour for their use sugar and salts3 the dough is kept warm as above explained4 ,under these conditions active fermentation takes place with the formation of alcohol and carbon dioxide gas4 ,the alcohol is of no particular consequence in bread making1 the small amount formed is probably expelled from the bread during its stay in the oven4 ,the carbon dioxide1 however1 plays a most important part4 ,being a gas it occupies a large volume1 and its formation throughout the mass of the dough causes the dough to increase greatly in volume4 ,the dough is said by the housewife to rise1 by the professional baker to prove4 ,illustration3 ,fig4 #af4 ,apparatus arranged for a baking test4 ,four loaves which have just been scaled and moulded are seen in an incubator where they are left to rise or prove before being transferred to the oven ,illustration3 ,fig4 #ag4 ,the loaves shown in the last figure have just been baked and are ready to be taken out of the oven1 the door of which is open4 ,note the different shapes4 ,that on the right hand is obviously shown by the test to be made from a strong flour1 the other from a very weak flour ,the process of kneading causes the particles of gluten to absorb water and to adhere to one another1 so that the dough may be regarded as being composed of innumerable bubbles each surrounded by a thin film of gluten1 in or between which lie the starch grains and other constituents of the flour4 ,each yeast cell as above explained forms a centre for the formation of carbon dioxide gas1 which cannot escape at once into the air1 and must therefore form a little bubble of gas inside the particular film of gluten which happens to surround it4 ,the expansion of the dough is due to the formation inside it of thousands of these small bubbles4 ,it is to the formation of these bubbles too that the porous honey-combed structure of wheaten bread is due4 ,also since the formation of the bubbles is due to the retention of the carbon dioxide by the gluten films1 such a porous structure is impossible in bread made from the flour of grains which do not contain gluten4 ,the rising of the dough is usually allowed to proceed for several hours4 ,the baker finds by experience how long a fermentation is required to give the best results with the flours he commonly uses4 ,when the proper time has elapsed1 the dough is removed from the trough or pan in which it was mixed to a board or table1 previously dusted with dry flour to prevent the dough adhering to the board or to the hands4 ,it is then divided into portions of the proper weight to make loaves of the desired size4 ,this process is known technically as scaling4 ,usually #b lbs4 #c ozs4 of dough is allowed for baking a #b lb4 loaf4 ,each piece of dough is now moulded into the proper shape if it is desired to bake what is known as a cottage loaf1 or placed in a baking tin if the baker is satisfied with a tinned loaf4 ,in either case the dough is once more kept for some time at a sufficiently warm temperature for the yeast to grow so that the dough may once more be filled with bubbles of carbon dioxide gas4 ,as soon as this second rising or proving has proceeded far enough the loaves are transferred to the oven4 ,here the intense heat causes the bubbles of gas inside the dough to expand so that a sudden increase in the size of the loaf takes place4 ,at the same time the outside of the loaf is hardened and converted into crust4 ,after remaining in the oven for the requisite time the bread is withdrawn and allowed to cool as quickly as possible1 after which it is ready for use or sale4 ,the method of baking which has been described above is known as the off-hand or straight dough method4 ,it possesses the merit of rapidity and simplicity1 but it is said by experts that it does not yield the best quality of bread from certain flours4 ,perhaps the commonest variation is that known as the sponge and dough method1 which is carried out as follows4 ,as before1 the requisite amount of flour is weighed out into the mixing trough1 and a depression made in it for the reception of the water and yeast4 ,these are mixed together in the proper proportions1 enough being taken to make a thick cream with about one quarter of the flour4 ,this mixture is now poured into the depression in the flour1 and enough of the surrounding flour stirred into it to make a thick cream or sponge as it is called4 ,at the same time a small quantity of salt is added to the mixture4 ,the sponge is allowed to ferment for some hours1 being kept warm as in the former method4 ,as soon as the time allowed for the fermentation of the sponge has elapsed1 more water is added1 so that the whole or nearly the whole of the flour can be worked up into dough4 ,this dough is immediately scaled and moulded into loaves1 which after being allowed to prove or rise for some time are baked as before4 ,this method is used for flours which do not yield good bread when they are submitted to long fermentation4 ,in such cases the mellow flours1 which will only stand a very short fermentation1 are first weighed out into the mixing trough1 and a depression made in the mass of flour into which a quantity of strong flour which can be fermented safely for a long time is added4 ,it is this last addition which is mixed up into the sponge to undergo the long preliminary fermentation4 ,the rest of the flour is mixed in after this first fermentation is over1 so that it is only subjected to the comparatively slight fermentation which goes on in the final process of proving4 ,many other modifications are commonly practised locally1 their object being for the most part to yield bread which suits the local taste4 ,it will suffice to mention one which has a special interest4 ,in this method the essentially interesting point is the preparation of what is known as a ferment4 ,for this purpose a quantity of potatoes is taken1 about a stone to the sack of flour4 ,after peeling and cleaning they are boiled and mashed up with water into a cream4 ,to this a small quantity of yeast is added and the mixture kept warm until fermentation ceases1 as shown by the cessation of the production of gas4 ,during this fermentation the yeast increases enormously1 so that a very small quantity of yeast suffices to make enough ferment for a sack of flour4 ,the flour is now measured out into the trough1 and the ferment and some additional water and salt added so that the whole can be worked up into dough4 ,scaling1 moulding1 and baking are then conducted as before4 ,this method was in general use years ago when yeast was dear4 ,it has fallen somewhat into disuse in these days of cheap compressed yeast1 in fact the use of potatoes nowadays would make the process expensive4 ,in private houses and in the smaller local bakeries the whole of the processes described above are carried out by hand4 ,during the last few decades many very large companies have been formed to take up the production of bread on the large scale4 ,this has caused almost a revolution of the methods of manipulating flour and dough1 and in many cases nowadays almost every process in the bakery is carried out by machinery4 ,in many of the larger bakeries doughing and kneading are carried out by machines1 and this applies also to the processes of scaling and moulding4 ,a similar change has taken place too in the construction of ovens4 ,years ago an oven consisted of a cavity in a large block of masonry4 ,wood was burned in the cavity until the walls attained a sufficiently high temperature4 ,the remains of the fuel were then raked out and the bread put in and baked by radiation from the hot walls4 ,nowadays it is not customary to burn fuel in the oven itself1 nor is the fuel always wood or even coal4 ,the fuel is burned in a furnace underneath the oven1 and coal or gas is generally used4 ,sometimes however the source of heat is electricity4 ,in all cases it is still recognised that the heat should be radiated from massive solid walls maintained at a high temperature4 ,in the latest type of oven the heat is conducted through the walls by closed iron tubes containing water1 which of course at the high temperatures employed becomes superheated steam4 ,it is recognised that the ovens commonly provided in modern private houses1 whether heated by the fire of the kitchen range1 or by gas1 are not capable of baking bread of the best quality1 because their walls do not radiate heat to the same degree as the massive walls of a proper bake oven4 ,it is commonly agreed that bread1 in the usual acceptation of the term1 should contain nothing but flour1 yeast1 salt1 and water2 or if other things are present they should consist only of the products formed by the interaction of these four substances in the process of baking4 ,millers and bakers have1 however1 found by experience that the addition of certain substances to the flour or to the dough may sometimes enable them substantially to improve the market value of the bread produced by certain flours4 ,the possible good or bad effect of such additions on the public health will be discussed in a later chapter4 ,it may be of interest here to mention some of the substances which are commonly used as flour or bread improvers by millers and bakers1 and to discuss the methods by which they effect their so called improvements4 ,in a former chapter we have discussed the quality of wheat from the miller's point of view1 and during the discussion certain views were enunciated on the subject of strength4 ,it was pointed out that a strong flour was one which would make a large well-shaped loaf1 and that the size of the loaf was dependent on the flour being able to provide sugar for the yeast to feed upon right up to the moment when the loaf goes into the oven4 ,this can only occur when the flour contains an active ferment which keeps changing the starch into sugar4 ,that this view is generally accepted in practice is shown by the fact that1 when using flours deficient in such ferment1 bakers commonly add to the flour1 yeast1 salt1 and water1 a quantity of malt extract1 the characteristic constituent of which is the sugar producing ferment of the malt4 ,this use of malt extract is now extending to the millers1 several of whom have installed in their mills plant for spraying into their flour a strong solution of malt extract4 ,it seems to be agreed by millers and bakers generally that such an addition to a flour which makes small loaves distinctly increases the size of the loaf4 ,there can be no doubt that this effect is produced by the ferment of the malt extract keeping up the supply of sugar1 and thus enabling the yeast to maintain the pressure of gas in the dough right up to the moment when it goes into the oven4 ,the view that the shape of the loaf is due to the effect of salts1 and particularly of phosphates1 on the coherence of the gluten has also been put to practical use by the millers and the bakers4 ,preparations of phosphates under various fancy names are now on the market1 and are bought by bakers for adding to the flour to strengthen the gluten and produce more shapely loaves4 ,a few millers too are beginning to spray solutions of phosphates into their flours with the same object in view1 and such additions are said to make material improvements in the shape of the loaf produced by certain weak flours4 ,these two substances1 malt extract and phosphates1 are added to the flour with the definite object of improving the strength and thus making larger and more shapely loaves4 ,but there is a second class of substances which are commonly added to flours1 not in the mill but in the process of bread making1 with the object of replacing yeast4 ,yeast is used in baking in order that it may form gas inside the dough and thus produce a light spongy loaf4 ,exactly the same gas can be readily and cheaply produced by the interaction of a carbonate with an acid4 ,these substances will not react to produce acid as long as they remain dry1 but as soon as they are brought into close contact with each other by the presence of water1 reaction begins and carbon dioxide gas is formed4 ,these facts are taken advantage of in the manufacture of baking powders and self-rising flours4 ,baking powders commonly consist of ordinary bicarbonate of soda mixed with an acid or an acid salt1 such as tartaric acid1 cream of tartar1 acid phosphate of lime1 or acid phosphate of potash4 ,one of these latter acid substances is mixed in proper proportions with the bicarbonate of soda1 and the mixture ground up with powdered starch which serves to dilute the chemicals and to keep them dry4 ,a small quantity of the baking powder is mixed with the flour before the water is added to make the dough4 ,the presence of the water causes the acid and the carbonate to give off gas which1 as in the case of the gas formed by the growth of yeast1 fills the dough with bubbles which expand in the oven and produce light spongy bread4 ,when using baking powders in place of yeast it must not be forgotten that gas formation in most cases begins immediately the water is added1 and lasts for a very short time4 ,consequently the dough must be moulded and baked at once or the gas will escape4 ,this is not the case1 however1 with those powders which are made with cream of tartar1 for this substance does not react with the carbonate to any great extent until the dough gets warm in the oven4 ,for some purposes it is customary to use carbonate of ammonia1 technically known as volatile1 in place of baking powder4 ,this substance is used alone without any addition of acid1 because it decomposes when heated and forms gas inside the dough4 ,sometimes too one or other of the baking powders above described are added to the flour by the miller1 the product being sold as self-rising flour4 ,such flour will of course lose its property of self-rising if allowed to get damp4 ,occasionally objectionable substances are used in making baking powders of self-rising flours4 ,some baking powders for instance contain alum which is not a desirable addition to any article of human food4 ,baking powders and self-rising flours are far more frequently used by house-wives for making pastry or for other kinds of domestic cookery than for breadmaking4 ,bread is made on the large scale without the intervention of yeast by the aeration process1 which is carried out as follows4 ,a small quantity of malt is allowed to soak in a large quantity of water1 and the solution thus obtained is kept warm so that it may ferment4 ,this charges the solution with gas and at the same time produces other substances which are supposed to give the bread a good flavour4 ,such a solution too retains gas much better than pure water4 ,this solution is then mixed with a proper proportion of flour inside a closed vessel1 carbon dioxide gas made by the action of acid on a carbonate being pumped into the vessel whilst the mixing is in progress4 ,the mixing is of course effected by mechanical means4 ,as soon as the dough is sufficiently mixed1 it is allowed to escape by opening a large tap at the bottom of the mixing vessel4 ,this it does quite readily being forced out by the pressure of gas inside4 ,as it comes out portions of suitable size to make a loaf are cut off4 ,these are at once moulded into loaves and put into the oven4 ,the gas which they contain expands1 and light well risen bread is produced4 ,this process is especially suited for wholemeal and other flours containing much offal1 which apparently do not give the best results when submitted to the ordinary yeast fermentation4 ,before closing this chapter it may be of interest to add a short account of the sale of bread4 ,bread is at the present time nominally sold by weight under acts of ,parliament passed about #hj years ago4 ,that is to say1 a seller of bread must provide in his shop scales and weights which will enable him to weigh the loaves he sells4 ,no doubt he would be prepared to do so if requested by a customer1 in which case he would probably make up any deficiency in weight which might be found by adding as a makeweight a slice from another loaf4 ,for this purpose it is commonly accepted that the ordinary loaf should weigh two pounds4 ,but in practice this does not occur1 for practically the whole of the bread which is sold in this country is sold from the baker's cart1 which delivers bread at the houses of customers1 and not over the counter4 ,customers obviously cannot be expected to wait at their doors whilst the man in the cart weighs each loaf he is delivering to them4 ,in actual practice therefore the bread acts1 as they are called1 are really a dead letter1 and bread is sold by the loaf and not by weight1 though it must be remembered that the loaf has the reputed weight of two pounds4 ,there are no doubt slight variations from this weight1 but for all practical purposes competition nowadays is quite as effective a check on the bona fides of the bread seller as enforced sale by weight would be likely to be4 ,if a baker got the reputation of selling loaves appreciably under weight his custom would very soon be transferred to one of his more scrupulous competitors4 ,altogether it may be concluded that the present unregulated method of sale does not work to the serious disadvantage of the consumers4 ,a little consideration will show that the sale of bread could only be put on a more scientific basis by the exercise of an enormous amount of trouble1 and the employment of a very numerous and expensive staff4 ,no doubt the ideally perfect way of regulating the sale of either bread or any other feeding stuff would be to enact that it should be sold by weight1 and that the seller should be compelled to state the percentage composition1 so that the buyer could calculate the price he was asked to pay per unit of actual foodstuff4 ,now bread normally contains #cf per cent4 of water1 but this amount varies greatly4 ,a two pound loaf kept in a dry place may easily lose water by evaporation at the rate of more than an ounce a day4 ,the baker usually weighs out #b lbs4 #c ozs4 of dough to make each two pound loaf1 and this amount yields a loaf which weighs in most cases fully two pounds soon after it comes out of the oven4 ,but if the weather is hot and dry such a loaf may very well weigh less than two pounds by the time it is delivered to the consumer4 ,in other words the baker cannot have the weight of the loaves he sells under complete control4 ,furthermore the loss in weight when a loaf gets dry by evaporation is due entirely to loss of water1 and does not decrease the amount of actual foodstuff in the loaf4 ,to sell bread in loaves guaranteed to contain a definite weight of actual foodstuff might be justified scientifically1 but practically it would entail so great an expense for the salaries of the inspectors and analysts required to enforce such a regulation that the idea is quite out of the question4 ,practically1 therefore1 the situation is that it would be unfair to enforce sale by weight pure and simple for the weight of a loaf varies according to circumstances which are outside the baker's control1 and further because the weight of the loaf is no guarantee of the weight of foodstuff present in it4 ,nor is it possible to enforce sale by guarantee of the weight of foodstuff in the loaf1 for to do so would be too troublesome and expensive4 ,finally the keenness of competition in the baking trade may be relied on to keep an efficient check on the interests of the consumer4 ,quite recently an important public authority has published the results of weighing several thousand loaves of bread purchased within its area of administration4 ,the results show that over half the two pound loaves purchased were under weight to the extent of five per cent4 on the average4 ,legislation is understood to be suggested as the result of this report1 in which case it is to be hoped that account will be taken of the fact that the food value of a loaf depends not only on its weight but also on the percentage of foodstuffs and water which it contains4 ,,chapter ,,vii ,,the ,,composition ,,of ,,bread ,bread is a substance which is made in so many ways that it is quite useless to attempt to give average figures showing its composition4 ,it will suffice for the present to assume a certain composition which is probably not far from the truth4 ,this will serve for a basis on which to discuss certain generalities as to the food-value of bread4 ,the causes which produce variation in composition will be discussed later1 together with their effect on the food value as far as information is available4 ,the following table shows approximately the composition of ordinary white bread as purchased by most of the population of this country4 per cent4 ,water #cf ,organic substances3 ,proteins #aj ,starch #db ,sugar1 etc4 #aj ,fat #a ,fibre #c #fcc ,ash3 ,phosphoric acid #b ,lime1 etc4 #e #g ------ #ajjj ,the above table shows that one of the most abundant constituents of ordinary bread is water4 ,flour as commonly used for baking1 although it may look and feel quite dry1 is by no means free from water4 ,it holds on the average about one-seventh of its own weight or #ad per cent4 ,in addition to this rather over one-third of its weight of water or about #ce to #dj per cent4 is commonly required to convert ordinary flour into dough4 ,it follows from this that dough will contain when first it is mixed somewhere about one-half its weight of water or #ej per cent4 ,about four per cent4 of the weight of the dough is lost in the form of water by evaporation during the fermentation of the dough before it is scaled and moulded4 ,usually #b lb4 #c oz4 of dough will make a two pound loaf1 so that about three ounces of water are evaporated in the oven1 ,this is about one-tenth the weight of the dough or #aj per cent4 ,together with the four per cent4 loss by evaporation during the fermenting period1 this makes a loss of water of about #ad per cent41 which1 when subtracted from the #ej per cent4 originally present in the dough1 leaves about #cf per cent4 of water in the bread4 ,as pointed out in the previous chapter this quantity is by no means constant even in the same loaf4 ,it varies from hour to hour1 falling rapidly if the loaf is kept in a dry place4 ,to turn now to the organic constituents4 ,the most important of these from the point of view of quantity is starch1 in fact this is the most abundant constituent of ordinary bread4 ,nor is it in bread only that starch is abundant4 ,it occurs to the extent of from #ej to #gj per cent4 in all the cereals1 grains1 wheat1 barley1 oats1 maize1 and rice4 ,potatoes too contain about #bj per cent4 of starch1 in fact it is present in most plants4 ,starch is a white substance which does not dissolve in cold water1 but when boiled in water swells up and makes1 a paste1 which becomes thick and semisolid on cooling4 ,it is this property which makes starch valuable in the laundry4 ,starch is composed of the chemical elements carbon1 hydrogen1 and oxygen4 ,when heated in the air it will burn and give out heat1 but it does not do so as readily as does fat or oil4 ,it is this property of burning and giving out heat which makes starch valuable as a foodstuff4 ,when eaten in the form of bread1 or other article of food1 it is first transformed by the digestive juices of the mouth and intestine into sugar1 which is then absorbed from the intestine into the blood1 and thus distributed to the working parts of the body4 ,here it is oxidized1 not with the visible flame which is usually associated with burning1 but gradually and slowly1 and with the formation of heat4 ,some of this heat is required to keep up the temperature of the body4 ,the rest is available for providing the energy necessary to carry on the movements required to keep the body alive and in health4 ,practically speaking therefore starch in the diet plays the same part as fuel in the steam engine4 ,the food value of starch can in fact be measured in terms of the quantity of heat which a known weight of it can give out on burning4 ,this is done by burning a small pellet of starch in a bomb of compressed oxygen immersed in a measured volume of water4 ,by means of a delicate thermometer the rise of temperature of the water is measured1 and it is thus found that one kilogram of starch on burning gives out enough heat to warm #da kilograms of water through one degree4 ,the quantity of heat which warms one kilogram of water through one degree is called one unit of heat or calorie1 and the amount of heat given out by burning one kilogram of any substance is called its heat of combustion or fuel-value4 ,thus the heat of combustion or fuel-value of starch is #da calories4 ,sugar has much the same food-value as starch1 in fact starch is readily changed into sugar by the digestive juices of the alimentary canal or by the ferments formed in germinating seeds4 ,from the point of view of food-value sugar may be regarded as digested starch4 ,like starch1 sugar is composed of the elements carbon1 hydrogen1 and oxygen4 ,like starch too its value in nutrition is determined by the amount of heat it can give out on burning1 and again its heat of combustion or fuel value #ci calories is almost the same as that of starch4 ,it will be noted that the whole of the #aj per cent4 quoted in the table as sugar1 etc41 is not sugar4 ,some of it is a substance called dextrin which is formed from starch by the excessive heat which falls on the outside of the loaf in the oven4 ,starch is readily converted by heat into dextrin1 and this fact is applied in many technical processes4 ,for instance much of the gum used in the arts is made by heating starch4 ,the outside of the loaf in the oven gets hot enough for some of the starch to be converted into dextrin4 ,dextrin is soluble in water like sugar and so appears with sugar in the analyses of bread4 ,from the point of view of food-value this is of no consequence1 as dextrin and sugar serve the same purpose in nutrition1 and have almost the same value as each other and as starch4 ,bread always contains a little fat1 not as a rule more that one or two per cent4 ,but although the quantity is small it cannot be neglected from the dietetic point of view4 ,fat is composed of the same elements as starch1 dextrin1 and sugar1 but in different proportions4 ,it contains far less oxygen than these substances4 ,consequently it burns much more readily and gives out much more heat in the process4 ,the heat of combustion or fuel value of fat is #ic calories or #bc times greater than that of starch4 ,evidently therefore even a small percentage of fat must materially increase the fuel value of any article of food4 ,but fat has an important bearing on the nutritive value of bread from quite another point of view4 ,in the wheat grain the fat is concentrated in the germ1 comparatively little being present in the inner portion of the grain4 ,thus the percentage of fat in any kind of bread is on the whole a very fair indication of the amount of germ which has been left in the flour from which the loaf was made4 ,it is often contended nowadays that the germ contains an unknown constituent which plays an important part in nutrition1 quite apart from its fuel-value4 ,on this supposition the presence of much fat in a sample of bread indicates the presence of much germ1 and presumably therefore much of this mysterious constituent which is supposed to endow such bread with a special value in the nutrition particularly of young children4 ,this question will be discussed carefully in a later chapter4 ,white bread contains a very small percentage of what is called by analysts fibre4 ,the quantity of this substance in a food is estimated by the analyst by weighing the residue which remains undigested when a known weight of the food is submitted to a series of chemical processes designed to imitate as closely as may be the action of the various digestive juices of the alimentary canal4 ,theoretically1 therefore1 it is intended to represent the amount of indigestible matter present in the food in question4 ,practically it does not achieve this result for some of it undoubtedly disappears during the passage of the food through the body4 ,it is doubtful however if the portion which disappears has any definite nutritive value4 ,that part of the fibre which escapes digestion and is voided in the excrement cannot possibly contribute to the nutrition of the body4 ,nevertheless it exerts a certain effect on the well-being of the consumer1 for the presence of a certain amount of indigestible material stimulates the lower part of the large intestine and thus conduces to regularity in the excretion of waste matters1 a fact of considerable importance in many cases4 ,the amount of fibre is an index of the amount of indigestible matter in a food4 ,in white bread it is small4 ,in brown breads which contain considerable quantities of the husk of the wheat grain it may be present to the extent of two or three per cent4 ,such breads therefore will contain much indigestible matter1 but they will possess laxative properties which make them valuable in some cases4 ,we have left to the last the two constituents which at the present time possess perhaps the greatest interest and importance1 the proteins and the ash4 ,the proteins of bread consist of several substances1 the differences between which1 for the present purpose1 may be neglected1 and we may assume that for all practical purposes the proteins of bread consist of one substance only1 namely gluten4 ,the importance of gluten in conferring on wheat flour the property of making light spongy loaves has already been insisted upon4 ,no doubt this property of gluten has a certain indirect bearing on the nutritive value of bread by increasing its palatability4 ,but gluten being a protein has a direct and special part to play in nutrition1 which is perhaps best illustrated by following one step further the comparison between the animal body and a steam engine4 ,it has been pointed out that starch1 sugar1 and fat play the same part in the body as does the fuel in a steam engine4 ,but an engine cannot continue running very long on fuel alone4 ,its working parts require renewing as they wear away1 and coal is no use for this purpose4 ,metal parts must be renewed with metal4 ,in much the same way the working parts of the animal body wear away1 and must be renewed with the stuff of which they are made4 ,now the muscles1 nerves1 glands and other working parts of the body are made of protein1 and they can only be renewed with protein4 ,consequently protein must be supplied in the diet in amount sufficient to make good from day to day the wear and tear of the working parts of the body4 ,it is for this reason that the protein of bread possesses special interest and importance4 ,protein like starch1 sugar1 and fat contains the elements carbon1 hydrogen1 and oxygen1 but it differs from them in containing also a large proportion of the element nitrogen1 which may be regarded as its characteristic constituent4 ,when digested in the stomach and intestine it is split into a large number of simpler substances known by chemists under the name of amino-acids4 ,every animal requires these amino-acids in certain proportions4 ,from the mixture resulting from the digestion of the proteins in its diet the amino-acids are absorbed and utilised by the body in the proportions required4 ,if the proteins of the diet do not supply the amino-acids in these proportions1 it is obvious that an excessive amount of protein must be provided in order that the diet may supply enough of that particular amino-acid which is present in deficient amount1 and much of those amino-acids which are abundantly present must go to waste4 ,this is undesirable for two reasons4 ,waste amino-acids are excreted through the kidneys1 and excessive waste throws excessive work on these organs1 which may lead to defective excretion1 and thus cause one or other of the numerous forms of ill health which are associated with this condition4 ,again1 excessive consumption of protein greatly adds to the cost of the diet1 for protein costs nearly as many shillings per pound as starch or sugar costs pence4 ,these considerations show clearly the wisdom of limiting the amount of protein in the diet to the smallest amount which will provide for wear and tear of the working parts4 ,the obvious way to do this is to take a mixed diet so arranged that the various articles of which the diet consists contain proteins which are so to speak complementary4 ,the meaning of this is perhaps best illustrated by a concrete example4 ,the protein of wheat1 gluten1 is a peculiar one4 ,on digestion it splits like other proteins into amino-acids1 but these are not present from the dietetic point of view in well balanced proportions4 ,one particular amino-acid1 called glutaminic acid1 preponderates1 and unfortunately this particular acid does not happen to be one which the animal organism requires in considerable quantity4 ,other amino-acids which the animal organism does require in large amounts are deficient in the mixture of amino-acids yielded by the digestion of the protein of wheat4 ,it follows1 therefore1 that to obtain enough of these latter acids a man feeding only on wheat products would have to eat a quantity of bread which would supply a great excess of the more abundant glutaminic acid1 which would go to waste with the evil results already outlined4 ,from this point of view it appears that bread should not form more than a certain proportion of the diet1 and that the rest of the diet should consist of foods which contain proteins yielding on digestion little glutaminic acid and much of the other amino-acids in which the protein of wheat is deficient4 ,unfortunately information as to the exact amount of the different amino-acids yielded by the digestion of the proteins even of many of the common articles of food is not available4 ,but many workers are investigating these matters1 and the next great advance in the science of dietetics will probably come along these lines4 ,by almost universal custom certain articles of food are commonly eaten in association3 bread and cheese1 eggs and bacon1 are instances4 ,such customs are usually found to be based on some underlying principle4 ,the principle in this case may well be that of complementary proteins4 ,the remarks which have been made above on the subject of the rle of protein in the animal economy apply to adults in which protein is required for wear and tear only and not for increase in weight4 ,they will obviously apply with greatly increased force to the case of growing children1 who require protein not only for wear and tear1 but for the building up of their muscles and other working parts as they grow and develope4 ,consequently the diet of children should contain more protein in proportion to their size than that of adults4 ,for this reason it is not desirable that bread should form an excessive proportion of their diet4 ,the bread they eat should be supplemented with some other food richer in protein4 ,the ash of bread although so small in amount cannot be ignored1 in fact it is regarded as of very great importance by modern students of dietetics4 ,the particular constituent of the ash to which most importance is attached is phosphoric acid4 ,this substance is a necessary constituent of the bones and of the brain and nerves of all animals4 ,it exists too in smaller proportions in other organs4 ,like other working parts of the body the bones and the nervous system are subject to wear and tear1 which must be replaced if the body is to remain in normal health4 ,a certain daily supply of phosphoric acid is required for this purpose1 and proportionally to their size more for children than for adults4 ,considerable difference of opinion as to the exact amount required is expressed by those who have investigated this question1 nor is it even agreed whether all forms of phosphoric acid are of the same value4 ,there is however a general recognition of the importance of this constituent of the diet1 and the subject is under investigation in many quarters4 ,,chapter ,,viii ,,concerning ,,different ,,kinds ,,of ,,bread ,the table given in the last chapter states the average composition of ordinary white bread baked in the form of cottage loaves1 and the remarks on the various constituents of bread in the preceding pages have for the most part referred to the same material1 though many of them may be taken to refer to bread in general4 ,it will now be of interest to inquire as to the variation in composition which is found among the different kinds of bread commonly used in this country4 ,this enquiry will be most readily conducted by first considering the possible causes which may affect the composition of bread4 ,the variation in the composition of bread is a subject which is taken up from time to time by the public press1 and debated therein with a great display of interest and some intelligent knowledge4 ,in most of the press discussions in the past interest has been focussed almost entirely on the effect of different kinds of milling4 ,the attitude commonly assumed by the food reform section of the contributors may be stated shortly as follows3 ,in the days of stone milling a less perfect separation of flour and bran was effected1 and the flour contained more of the materials situated in the grain near the husk than do the white flours produced by modern methods of roller milling4 ,again the modern roller mills separate the germ from the flour1 which the stone mills fail to do1 at any rate so completely4 ,thus the stone ground flours contain about #hj per cent4 of the grain1 whilst the whole of the flour obtained from the modern roller mill seldom amounts to much more than about #gb per cent4 ,the extra eight per cent4 of flour produced in the stone mills contains all or nearly all the germ and much of the material rich in protein which lies immediately under the husk4 ,hence the stone ground flour is richer in protein1 and in certain constituents of the germ1 than white roller mill flour1 and hence again stone ground flour has a higher nutritive value4 ,roller mill flour has nothing to commend it beyond its whiteness4 ,it has been suggested that millers should adopt the standard custom of producing #hj per cent4 of flour from all the wheat passing through their mills and thus retain those constituents of the grain which possess specially great nutritive value4 ,it would probably be extremely difficult to produce #hj per cent4 of flour from many kinds of wheat1 but for the present this point may be ignored1 whilst we discuss the variation in the actual chemical composition of the flour produced as at present and on the #hj per cent4 basis4 ,in comparing the chemical composition of different kinds of flour it is obvious that the flours compared must have been made from the same lot of wheat1 for as will be seen later different wheats vary greatly in the proportions of protein and other important constituents which they contain4 ,unfortunately the number of analyses of different flours made from the same lots of wheat is small4 ,perhaps the best series is that published by ,dr ,hamill in a recent report of the ,local ,government ,board4 ,dr ,hamill gives the analyses of five different grades of flour made at seven mills1 each mill using the same blend of wheats for all the different kinds of flour4 ,calculating all these analyses to a basis of #aj per cent4 of protein in the grade of flour known as patents1 the figures on the opposite page were obtained1 which may be taken to represent with considerable accuracy the average composition of the various kinds of flours and offals when made from the same wheat4 ,description of flour ,protein ,phosphoric acid or offal per cent4 per cent4 ,flours3 ,patents #ajj #jah ,straight grade1 about #gj per cent4 #ajf #jba ,households #aji #jbf ,standard flour1 about #hj per cent4 #aaj #jce ,wholemeal #aac #jgc ,offals3 ,germ #bdj #bbb ,sharps #ade #aff ,bran #ace #bej ,accepting these figures as showing the relative proportions of protein and phosphoric acid in different flours as affected by milling only1 other sources of variation having been eliminated by the use of the same blend of wheat1 it appears that the flours of commercially higher grade undoubtedly do contain somewhat less protein and phosphoric acid than lower grade or wholemeal flours4 ,taking the extreme cases of patents and wholemeal flours1 the latter contains one-ninth more protein and four times more phosphoric acid than the former1 provided both are derived from the same wheat4 ,in actual practice1 however1 it generally happens that the higher grade flours are made from a blend of wheats containing a considerable proportion of hard foreign wheats which are rich in nitrogen1 whilst wholemeal and standard flours are usually made from home grown wheats which are relatively poor in nitrogen4 ,from a number of analyses of foreign and home grown wheats it appears that the relative proportions of protein is about #ab per cent4 in the hard foreign wheats as compared with #aj per cent4 in home grown wheats4 ,thus the presence of a larger proportion of protein in the hard wheats used in the blend of wheat for making the higher grade flours must tend to reduce the difference in protein content between say patents and wholemeal flours as met with in ordinary practice4 ,furthermore much of the bread consumed by that part of the population to whom a few grams per day of protein is of real importance is1 or should be1 made1 for reasons of economy1 from households flour1 and the disparity between this grade of flour and wholemeal flour is much less than is the case with patents4 ,it appears1 therefore1 on examining the facts1 that there is no appreciable difference in the protein content of the ordinary white flours consumed by the poorer classes of the people and wholemeal flour or standard flour4 ,in the above paragraphs account has been taken only of the total amount of protein in the various kinds of bread and flour4 ,it is obvious1 however1 that the total amount present is not the real index of food-value4 ,only that portion of any article of diet which is digested in the alimentary canal can be absorbed into the blood and carried thereby to the tissues where it is required to make good wear and tear4 ,the real food-value must therefore depend not on the total amount of foodstuff present but on the amount which is digestible4 ,the proportion of protein which can be digested in the different kinds of bread has been the subject of careful experiments in ,america1 and lately in ,cambridge4 ,the method of experimenting is arduous and unpleasant4 ,several people must exist for a number of days on a diet consisting chiefly of the kind of bread under investigation1 supplemented only by small quantities of food which are wholly digestible1 such as milk1 sugar and butter4 ,during the experimental period the diet is weighed and its protein content estimated by analysis4 ,the excreta are also collected and their protein content estimated by analysis1 so that the amount of protein which escapes digestion can be ascertained4 ,the experiment is then repeated with the same individuals and the same conditions in every way except that another kind of bread is substituted for the one used before4 ,from the total amount of protein consumed in each kind of bread the total amount of protein voided in the excreta is subtracted1 and the difference gives the amount which has been digested and presumably utilised in the body4 ,from these figures it is easy to calculate the number of parts of protein digested for every #ajj parts of protein eaten in each kind of bread4 ,this description will have made evident the unpleasant nature of such experimental work4 ,its laboriousness will be understood from the fact that a series of experiments of this kind carried out at ,cambridge last winter necessitated four people existing for a month on the meagre diet above mentioned1 and entailed over #ajjj chemical analyses4 ,the following table shows the amounts of protein digested per #ajj parts of protein consumed in bread made from various kinds of flour1 as based on the average of a number of experiments made in ,america1 and in the experiments at ,cambridge above referred to4 ,kind of flour from ,percentage of ,amount of protein digested which bread the grain per #ajj parts eaten was made contained in ,american ,cambridge the flour experiments experiments ,patents #cf -- #hi ,straight grade #gj #hi -- ,standard #hj #ha #hf ,brown #hh -- #hj ,brown #ib -- #gg ,wholemeal #ajj #gf -- ,the ,american and the ,cambridge figures agree very well with each other1 and this gives confidence in the reliability of the results4 ,it appears to be quite certain therefore that the protein in bread made from the higher grade flours is very considerably more digestible than that contained in bread made from flours containing greater amounts of husk4 ,the percentages following the names of the various grades of flour in the first column of the table indicate approximately the proportion of the whole grain which went into the flour to which the figure is attached4 ,looking down these figures it appears that the digestibility of the protein decreases as more and more of the grain is included in the flour4 ,it follows1 therefore1 that whilst by leaving more and more of the grain in the flour we increase the percentage of protein in the flour1 and consequently in the bread1 at the same time we decrease the digestibility of the protein4 ,apparently1 too1 this decrease in digestibility is proportionally greater than the increase in protein content1 and it follows therefore that breads made from low grade flours containing much husk will supply less protein which is available for the use of the body1 although they may actually contain slightly more total protein than the flours of higher grade4 ,when all the facts are taken into account it appears that the contention of the food reformers1 that the various breads which contain those constituents of the grain which lie near the husk are capable of supplying more protein for the needs of the body than white breads1 cannot be upheld4 ,from statistics collected by the ,board of ,trade some few years ago as to the dietary of the working classes it appears that the diet of workers both in urban and in rural districts contains about #ig grams of total protein per head per day4 ,this is rather under than over the commonly accepted standard of #ajj grams of protein which is supposed to be required daily by a healthy man at moderate work4 ,consequently a change in his diet which increased the amount of protein might be expected to be a good change4 ,but the suggested change of brown bread for white1 though it appears to increase the total protein1 turns out on careful examination to fail in its object1 for it does not increase the amount of protein which can be digested4 ,from the same statistics it appears that the diet of a working man includes on the average about #a lb4 of bread per day4 ,this amount of bread contains about #fj grams of protein1 or two-thirds of the total protein of the diet4 ,now it was pointed out in the last chapter that the protein of wheat was very rich in glutaminic acid1 a constituent of which animals require comparatively small amounts4 ,it is also correspondingly poor in certain constituents which are necessary to animals4 ,apparently therefore it would be better to increase the diet in such cases by adding some constituent not made from wheat than by changing the kind of bread4 ,from the protein point of view1 however we look at it1 there appears to be no real reason for substituting one or other of the various kinds of brown bread for the white bread which seems to meet the taste of the present day public4 ,but important as protein is it is not everything in a diet4 ,as we have already pointed out the food must not only repair the tissues1 it must also supply fuel4 ,it has been shown also that the fuel-value of a food can be ascertained by burning a known weight and measuring the number of units of heat or calories produced4 ,many samples of bread have been examined in this way in the laboratories of the ,american ,department of ,agriculture1 and it appears from the figures given in their bulletins that the average fuel value of white bread is about #abej calories per pound1 of wholemeal bread only #aaej calories per pound4 ,these figures are quite in accord with those which were obtained in ,cambridge in #aiaa1 in connection with the digestion experiments already described1 which were also extended so as to include a determination of the proportion of the energy of the bread which the diet supplied to the body4 ,the energy or fuel-value of the diet was determined by measuring the amount of heat given out by burning a known weight of each of the kinds of bread used in the experiment4 ,the energy which was not utilised by the body was then determined by measuring how much heat was given out by burning the excreta corresponding to each kind of bread4 ,the following table gives side by side the average results obtained in several such experiments in ,america and in ,cambridge4 ,the agreement between the two sets of figures is again on this point quite satisfactory4 ,it is evident that a greater proportion of the total energy of white bread can be utilised by the body than is the case with any of the breads made from flours of lower commercial grades which contain more husk4 ,in fact it appears that the more of the outer parts of the grain are left in the flour the smaller is the proportion of the total energy of the bread which can be utilised4 ,combining this conclusion with the fact that brown breads contain on the average less total energy than white breads1 there can be no doubt that white bread is considerably better than any form of brown bread as a source of energy for the body4 ,kind of flour from ,percentage of ,amount of energy utilised which the bread the grain per #ajj units in food was made contained in ,american ,cambridge the flour experiments experiments ,patents #cf #if #if ,straight grade #gj #ib -- ,standard #hj #hg #ie ,brown #hh -- #ij ,brown #ib -- #hi ,wholemeal #ajj #hb -- ,there is one more important substance in respect of which great superiority is claimed for brown breads1 namely phosphoric acid4 ,from the table on page #abb there can be no doubt that flours containing more of the outer parts of the grain are very much richer in phosphoric acid than white flours1 and the disparity is so great that after allowing for the larger proportion of water in brown breads they must contain far more of this substance than do white breads4 ,in the ,cambridge digestibility experiments quoted above the proportion of the phosphoric acid digested from the different breads was determined4 ,it was found that for every #ajj parts of phosphoric acid in white bread only #eb parts were digested1 and that in the case of the brown breads this proportion fell to #da parts out of #ajj4 ,again1 as in the case of protein and energy1 the phosphoric acid in white bread is more readily available to the body than that of brown bread1 but in this case the difference in digestibility is not nearly enough to counterbalance the much larger proportion of phosphoric acid in the brown bread4 ,there is no doubt that the body gets more phosphoric acid from brown bread than from the same quantity of white bread4 ,but before coming to any practical conclusion it is necessary to know two things1 how much phosphoric acid does a healthy man require per day1 and does his ordinary diet supply enough8 ,from the ,board of ,trade statistics already quoted it appears that1 on the assumption that the average worker eats white bread only1 his average diet contains #bd grams of phosphoric acid per day1 which would be raised to #cb grams if the white bread were replaced by bread made from #hj per cent4 flour containing #ce per cent4 of phosphoric acid4 ,information as to the amount of phosphoric acid required per day by a healthy man is somewhat scanty1 and indicates that the amount is very variable1 but averages about #b grams per day4 ,if this is so1 the ordinary diet with white bread provides on the average enough phosphoric acid4 ,exceptional individuals may1 however1 be benefited by the substitution of brown bread for white1 but it would probably be better even in such cases1 for the reasons stated when discussing the protein question1 to raise the phosphorus content of their diet by the addition of some substance rich in phosphorus but not made from wheat4 ,finally comes the question of the variation in the composition of bread due to the presence or absence of the germ4 ,the first point in this connection is to decide whether germ is present in appreciable proportions in any flour except wholemeal4 ,the germ is a soft moist substance which flattens much more readily than it grinds4 ,consequently it is removed from flour by almost any kind of separation1 even when very coarse sieves are employed4 ,if this contention is correct no flour except wholemeal should contain any appreciable quantity of germ1 and it is certainly very difficult to demonstrate the presence of actual germ particles even in #hj per cent4 flour4 ,indirect evidence of the presence of germ may1 however1 be obtained as already explained by estimating by chemical analysis the proportion of fat present in various flours4 ,the figures for such estimations are given by ,dr ,hamill in the report of the ,local ,government ,board already referred to4 ,they show that the percentages of fat in different grades of flours made from the same blends of wheat are on the average of seven experiments as follows3 patents flour #if3 household flours #abe3 #hj per cent4 or standard flour #adb4 ,these figures show that the coarser flours containing more of the whole grain do contain more germ than the flours of commercially higher grade1 in spite of the fact that it is difficult to demonstrate its presence under the microscope4 ,remembering1 however1 that the whole of the germ only amounts to about #a per cent4 of the grain1 it is clear that the presence or absence of more or less germ cannot appreciably affect the food-value as measured by protein content or energy-value4 ,it is still open to contention that the germ may contain some unknown constituent possessing a peculiar effect on nutrition4 ,such a state of things can well be imagined in the light of certain experimental results which have been obtained during the last few years4 ,it has been shown for instance by ,dr ,hopkins in ,cambridge1 and his results have been confirmed at the ,carnegie ,institute in ,america1 that young rats fail to thrive on a diet composed of suitable amounts of purified protein1 fat1 starch1 and ash1 but that they thrive and grow normally on such a diet if there is added a trace of milk or other fresh animal or vegetable substance far too small to influence either the protein content or the energy-value4 ,another case in point is the discovery that the disease known as beri beri1 which is caused by a diet consisting almost exclusively of rice from which the husk has been removed1 can be cured almost at once by the administration of very small doses of a constituent existing in minute quantities in rice husk4 ,the suggestion is that high grade flours1 like polished rice1 may fail to provide some substance which is necessary for healthy growth1 a substance which is removed in the germ or husk when such flours are purified1 and which is present in flours which have not been submitted to excessive purification4 ,the answer is that no class in ,great ,britain lives on bread exclusively4 ,bread appears from the government statistics already quoted to form only about half the diet of the workers of the country4 ,their diet includes also some milk1 meat1 and vegetables1 and such substances1 according to ,dr ,hopkins' experiments1 certainly contain the substance1 whatever it may be1 that is missing from the artificial diet on which his young rats failed to thrive4 ,one last point4 ,it will have been noticed in the figures given above that the variations in protein content1 digestibility1 and energy-value1 between different kinds of bread are usually not very large4 ,there is1 however1 one constituent of all breads whose proportions vary far more widely1 namely water4 ,during last summer the author purchased many samples of bread in and around ,cambridge1 and determined the percentage of water in each sample4 ,the samples were all one day old so that they are comparable with one another4 ,the results on the whole are a little low1 probably because the work was done during a spell of rather dry weather1 when the loaves would lose water rapidly4 ,the average figures are summarised below3 ,percentage of water ,cottage loaves made of white flour #cag ,tinned loaves made of white flour #cbg ,small fancy loaves made of white flour #ccg ,tinned loaves made of 8,standard0 flour #cei ,tinned loaves made of brown or germ flour #djj ,the figures speak for themselves4 ,there must obviously be more actual food in a cottage loaf of white flour containing under #cb per cent4 of water than in any kind of ,standard or brown loaf in which the percentage of water is #cf to #dj4 ,it is quite extraordinary that no one who has organised any of the numerous bread campaigns in the press appears to have laid hold of the enormous variation in the water content of different kinds of bread1 and its obvious bearing on their food-value4 ,,bibliography ,the reader who wishes further information on any of the numerous subjects connected with the growth1 manipulation and composition of breadstuffs is referred to the following publications1 to which among others the author is much indebted4 ,the list is arranged1 as far as possible1 in the same order as the chapters of the book4 ,,chapter ,i4 ,the ,book of the ,rothamsted ,experiments1 by ,a4 ,d4 ,hall4 7,john ,murray1 #aije47 ,the ,feeding of ,crops and ,stock1 by ,a4 ,d4 ,hall4 7,john ,murray1 #aiaa47 ,fertilizers and ,manures1 by ,a4 ,d4 ,hall4 7,john ,murray1 #aiji47 ,the ,soil1 by ,a4 ,d4 ,hall4 7,john ,murray1 #aijh47 ,agriculture and ,soils of ,kent1 ,surrey1 and ,sussex1 by ,a4 ,d4 ,hall and ,e4 ,j4 ,russell4 7,board of ,agriculture and ,fisheries47 ,some ,characteristics of the ,western ,prairie ,soils of ,canada1 by ,frank ,t4 ,shutt4 7,journal of ,agricultural ,science1 ,vol4 ,,iii1 p4 #cce47 ,dry ,farming3 its ,principles and ,practice1 by ,wm ,macdonald4 7,t4 ,werner ,laurie47 ,profitable ,clay ,farming1 by ,john ,prout4 7#ahha47 ,continuous ,corn ,growing1 by ,w4 ,a4 ,prout and ,j4 ,augustus ,voelcker4 7,journal of the ,royal ,agricultural ,society of ,england1 #aije47 ,,chapter ,,ii4 ,the ,wheat ,problem1 by ,sir ,w4 ,crookes4 7,john ,murray1 #ahii47 ,the ,production of ,wheat in the ,british ,empire1 by ,a4 ,e4 ,humphries4 7,journal of the ,royal ,society of ,arts1 ,vol4 ,,lvii1 p4 #bbi47 ,wheat ,growing in ,canada1 the ,united ,states1 and the ,argentine1 by ,w4 ,p4 ,rutter4 7,adam and ,charles ,black1 #aiaa47 ,agricultural ,note-,book1 by ,primrose ,mc,connell4 7,crosby1 ,lockwood and ,son1 #aiaj47 ,,chapter ,,iii4 ,agricultural ,botany1 by ,j4 ,percival4 7,duckworth and ,co41 #aijj47 ,the ,interpretation of the ,results of ,agricultural ,experiments1 by ,t4 ,b4 ,wood1 and ,field ,trials and their interpretation1 by ,a4 ,d4 ,hall and ,e4 ,j4 ,russell4 7,journal of the ,board of ,agriculture and ,fisheries1 ,supplement ,no4 #g1 ,nov4 #aiaa47 ,heredity in ,plants and ,animals1 by ,t4 ,b4 ,wood and ,r4 ,c4 ,punnett4 7,journal of the ,highland and ,agricultural ,society of ,scotland1 ,vol4 ,,xx1 ,fifth ,series1 #aijh47 ,mendelism1 by ,r4 ,c4 ,punnett4 7,macmillan and ,co41 #aiaa47 ,mendel's ,laws and ,wheat ,breeding1 by ,r4 ,h4 ,biffen4 7,journal of ,agricultural ,science1 ,vol4 ,i1 p4 #d47 ,studies in the ,inheritance of ,disease ,resistance1 by ,r4 ,h4 ,biffen4 7,journal of ,agricultural ,science1 ,vol4 ,,ii1 p4 #aji2 ,vol4 ,,iv1 p4 #dba47 ,the ,inheritance of ,strength in ,wheat1 by ,r4 ,h4 ,biffen4 7,journal of ,agricultural ,science1 ,vol4 ,,iii1 p4 #hf47 ,variation1 ,heredity1 and ,evolution1 by ,r4 ,h4 ,lock4 7,john ,murray1 #aiji47 ,minnesota ,wheat ,breeding1 by ,willet ,m4 ,hays and ,andrew ,boss4 7,mc,gill-,warner ,co41 ,st ,paul47 ,the ,improvement of ,english ,wheat1 by ,a4 ,e4 ,humphries and ,r4 ,h4 ,biffen4 7,journal of ,agricultural ,science1 ,vol4 ,,ii1 p4 #a47 ,plant ,breeding in ,scandinavia1 by ,l4 ,h4 ,newman4 7,the ,canadian ,seed ,growers ,association1 ,ottawa1 #aiab47 ,,chapters ,,iv1 ,v1 ,,and ,,vi4 ,the ,technology of ,bread ,making1 by ,w4 ,jago4 7,simpkin1 ,marshall and ,co41 #aiaa47 ,modern ,development of ,flour ,milling1 by ,a4 ,e4 ,humphries4 7,journal of the ,royal ,society of ,arts1 ,vol4 ,,lv1 p4 #aji47 ,home ,grown ,wheat ,committee's ,reports4 7#ei1 ,mark ,lane1 ,london1 ,e4,c47 ,the ,chemistry of ,strength of ,wheat ,flour1 by ,t4 ,b4 ,wood4 7,journal of ,agricultural ,science1 ,vol4 ,,ii1 pp4 #aci1 #bfg47 ,,chapters ,,vii ,,and ,,viii4 ,composition and ,food ,value of ,bread1 by ,t4 ,b4 ,wood4 7,journal of the ,royal ,agricultural ,society of ,england1 #aiaa47 ,some ,experiments on the ,relative ,digestibility of ,white and ,whole-meal ,breads1 by ,l4 ,f4 ,newman1 ,g4 ,w4 ,robinson1 ,e4 ,t4 ,halnan1 and ,h4 ,a4 ,d4 ,neville4 7,journal of ,hygiene1 ,vol4 ,,xii1 ,no4 #b47 ,nutritive ,value of ,bread1 by ,j4 ,m4 ,hamill4 7,local ,government ,board ,report1 ,cd4 #ehca47 ,bleaching and ,improving ,flour1 by ,j4 ,m4 ,hamill and ,g4 ,w4 ,monier ,williams4 7,local ,government ,board ,report1 ,cd4 #efac47 ,diet of ,rural and ,urban ,workers4 7,board of ,trade ,reports1 ,cd4 #agfa and #bccg47 ,bulletins of the ,u4,s4,a4 ,department of ,agriculture4 7,division of ,chemistry #ac2 ,office of ,experiment ,stations #ba1 #eb1 #fg1 #he1 #aja1 #abf1 #aef1 #ahe1 #bbg47 ,,index ,aerated bread1 #ajd ,amino-acids1 #aaf ,ash of bread1 #aai ,baking1 #fc1 #ia ,baking powders1 #ajb ,biffen's new varieties1 #di1 #ei method1 #da1 #df1 #eh ,bread1 amount in diet1 #abg composition of1 #aji variations in1 #abj water in1 #ace ,break rolls1 #ha ,breeding of wheat1 #bi1 #ce1 #dj ,burgoyne's ,fife1 #ei ,climate suitable for wheat1 #b1 #bh ,clover as preparation for wheat1 #h ,colloids1 #fg ,continuous growth of wheat1 #g ,crookes1 ,sir ,w41 shortage of nitrogen1 #e ,cropping power of wheats1 #cb ,cross-breeding1 #dj ,digestibility of bread1 #abd ,dressing wheat1 #af ,dry farming1 #aj ,elements required by wheat1 #b ,energy-values1 #aaa ,fat in bread1 #aac ,fermentation in dough1 #id ,fibre1 #aad ,field plots1 accuracy of1 #cb ,fife wheat1 #dg1 #eg ,flour1 composition of1 #abb grades of1 #hh1 #abb self-rising1 #ajb ,food-value of various breads1 #abj of starch1 etc4 in bread1 #aaj ,foreign wheat growing1 #ba ,fuel-values1 #aaa ,futures1 #bf ,germ1 food-value of1 #acb in milling1 #hi in bread1 #aad1 #acb ,gluten1 #fc properties of1 #fh ,grades of flour1 #hh1 #abb of wheat1 #bc ,home ,grown ,wheat ,committee1 #ec1 #ef ,hopkins' work1 #acb ,hybridisation1 #dj ,improvers1 flour1 #ajj ,indigestible matter in bread1 #aad ,inheritance in wheat1 #da ,johannsen1 #cg ,judging wheats1 #fj ,lawes and ,gilbert1 #d ,liebig1 #c ,little ,joss wheat1 #ea ,manuring wheat1 #c1 #g ,markets1 home1 #af foreign1 #bb1 #bg ,market quotations1 #ai ,mendel's laws1 #dj ,milling1 history of1 #gd1 #gg effect of1 on flour1 #abb ,mineral manures1 #c ,minnesota experiments1 #cf ,natural moisture in wheat1 #eb ,nitrogen1 cost of1 in manures1 #d fixation1 #h for wheat1 #d from air1 #f scarcity of1 #e synthetic1 #f ,ovens for baking1 #ii ,patents flour1 #hh ,pedigree in wheat1 #ci ,phosphates in bread1 #aai in diet1 #aca in flour1 #gj ,plots for yield testing1 #cb ,protein1 cost of1 in diet1 #aaf in bread1 #aae ,prout's system of farming1 #g ,pure-line theory1 #cg ,purification of flour1 #hf ,rainfall for wheat1 #b ,red ,fife1 #dg ,reduction rolls1 #hg ,roller mill1 #gi ,rotation of crops1 #i ,rothamsted experiments1 #d ,rust-proof wheat1 #ea ,sale of bread1 #aje of wheat1 #af ,scaling loaves1 #if ,selection for cropping power1 #ce ,self-rising flour1 #ajb ,separation of flour1 #he ,semolina1 #hf ,sheep-folding1 #aj ,soils for wheat1 #b 8,standard0 flour1 #ace ,starch in bread1 #aaj ,stone mill1 #ge ,strength of flour1 cause of1 #fb of flour1 test for1 #ff1 #gb of wheat or flour1 #ec ,strong wheats1 characters of1 #fj value of1 #ei ,sugar in bread1 #aab ,synthetic nitrogenous manures1 #f ,thrashing wheat1 #ae ,turbidity test for strong wheats1 #gc ,variety of wheat1 choice of1 #bh testing1 #cb ,virgin soils1 #e ,water in bread1 #aji1 #ace ,weak wheats1 characters of1 #fa ,weights and measures1 #ag ,yeast1 growth in dough1 #id ,yield of wheat1 conditions of1 #bh ,,cambridge3 ,,printed ,,by ,,john ,,clay1 ,m4,a4 ,,at ,,the ,,university ,,press ,,the ,,cambridge ,,manuals ,,of ,,science ,,and ,,literature ,published by the ,cambridge ,university ,press ,,general ,,editors ,p4 ,,giles1 ,litt4,d4 ,master of ,emmanuel ,college and ,a4 ,c4 ,,seward1 ,m4,a41 ,f4,r4,s4 ,professor of ,botany in the ,university of ,cambridge ,,sixty ,,volumes ,,now ,,ready ,,history ,,and ,,archaeology ,ancient ,assyria4 ,by ,rev4 ,c4 ,h4 ,w4 ,johns1 ,litt4,d4 ,ancient ,babylonia4 ,by ,rev4 ,c4 ,h4 ,w4 ,johns1 ,litt4,d4 ,a ,history of ,civilization in ,palestine4 ,by ,prof4 ,r4 ,a4 ,s4 ,macalister1 ,m4,a41 ,f4,s4,a4 ,china and the ,manchus4 ,by ,prof4 ,h4 ,a4 ,giles1 ,,ll4,d4 ,the ,civilization of ,ancient ,mexico4 ,by ,lewis ,spence4 ,the ,vikings4 ,by ,prof4 ,allen ,mawer1 ,m4,a4 ,new ,zealand4 ,by the ,hon4 ,sir ,robert ,stout1 ,k4,c4,m4,g41 ,,ll4,d41 and ,j4 ,logan ,stout1 ,,ll4,b4 7,n4,z474 ,the ,ground ,plan of the ,english ,parish ,church4 ,by ,a4 ,hamilton ,thompson1 ,m4,a41 ,f4,s4,a4 ,the ,historical ,growth of the ,english ,parish ,church4 ,by ,a4 ,hamilton ,thompson1 ,m4,a41 ,f4,s4,a4 ,brasses4 ,by ,j4 ,s4 ,m4 ,ward1 ,b4,a41 ,f4,r4,hist4,s4 ,ancient ,stained and ,painted ,glass4 ,by ,f4 ,s4 ,eden4 ,,literary ,,history ,the ,early ,religious ,poetry of the ,hebrews4 ,by the ,rev4 ,e4 ,g4 ,king1 ,d4,d4 ,the ,early ,religious ,poetry of ,persia4 ,by the ,rev4 ,prof4 ,j4 ,hope ,moulton1 ,d4,d41 ,d4,theol4 7,berlin74 ,the ,history of the ,english ,bible4 ,by the ,rev4 ,john ,brown1 ,d4,d4 ,english ,dialects from the ,eighth ,century to the ,present ,day4 ,by ,w4 ,w4 ,skeat1 ,litt4,d41 ,d4,c4,l41 ,f4,b4,a4 ,king ,arthur in ,history and ,legend4 ,by ,prof4 ,w4 ,lewis ,jones1 ,m4,a4 ,the ,icelandic ,sagas4 ,by ,w4 ,a4 ,craigie1 ,,ll4,d4 ,greek ,tragedy4 ,by ,j4 ,t4 ,sheppard1 ,m4,a4 ,the ,ballad in ,literature4 ,by ,t4 ,f4 ,henderson4 ,goethe and the ,twentieth ,century4 ,by ,prof4 ,j4 ,g4 ,robertson1 ,m4,a41 ,ph4,d4 ,the ,troubadours4 ,by the ,rev4 ,h4 ,j4 ,chaytor1 ,m4,a4 ,,philosophy ,,and ,,religion ,the ,idea of ,god in ,early ,religions4 ,by ,dr ,f4 ,b4 ,jevons4 ,comparative ,religion4 ,by ,dr ,f4 ,b4 ,jevons4 ,the ,moral ,life and ,moral ,worth4 ,by ,prof4 ,sorley1 ,litt4,d4 ,the ,english ,puritans4 ,by the ,rev4 ,john ,brown1 ,d4,d4 ,an ,historical ,account of the ,rise and ,development of ,presbyterianism in ,scotland4 ,by the ,rt4 ,hon4 the ,lord ,balfour of ,burleigh1 ,k4,t41 ,g4,c4,m4,g4 ,methodism4 ,by ,rev4 ,h4 ,b4 ,workman1 ,d4,lit4 ,,education ,life in the ,medieval ,university4 ,by ,r4 ,s4 ,rait1 ,m4,a4 ,,economics ,cash and ,credit4 ,by ,d4 ,a4 ,barker1 ,i4,c4,s4 ,,law ,the ,administration of ,justice in ,criminal ,matters 7in ,england and ,wales74 ,by ,g4 ,glover ,alexander1 ,m4,a41 ,,ll4,m4 ,,biology ,the ,coming of ,evolution4 ,by ,prof4 ,j4 ,w4 ,judd1 ,c4,b41 ,f4,r4,s4 ,heredity in the ,light of ,recent ,research4 ,by ,l4 ,doncaster1 ,m4,a4 ,primitive ,animals4 ,by ,geoffrey ,smith1 ,m4,a4 ,the ,individual in the ,animal ,kingdom4 ,by ,j4 ,s4 ,huxley1 ,b4,a4 ,life in the ,sea4 ,by ,james ,johnstone1 ,b4,sc4 ,the ,migration of ,birds4 ,by ,t4 ,a4 ,coward4 ,spiders4 ,by ,c4 ,warburton1 ,m4,a4 ,house ,flies4 ,by ,c4 ,g4 ,hewitt1 ,d4,sc4 ,earthworms and their ,allies4 ,by ,f4 ,e4 ,beddard1 ,f4,r4,s4 ,,anthropology ,the ,wanderings of ,peoples4 ,by ,dr ,a4 ,c4 ,haddon1 ,f4,r4,s4 ,prehistoric ,man4 ,by ,dr ,w4 ,l4 ,h4 ,duckworth4 ,,geology ,rocks and their ,origins4 ,by ,prof4 ,grenville ,a4 ,j4 ,cole4 ,the ,work of ,rain and ,rivers4 ,by ,t4 ,g4 ,bonney1 ,sc4,d4 ,the ,natural ,history of ,coal4 ,by ,dr ,e4 ,a4 ,newell ,arber4 ,the ,natural ,history of ,clay4 ,by ,alfred ,b4 ,searle4 ,the ,origin of ,earthquakes4 ,by ,c4 ,davison1 ,sc4,d41 ,f4,g4,s4 ,,botany ,plant-,animals3 a ,study in ,symbiosis4 ,by ,prof4 ,f4 ,w4 ,keeble4 ,plant-,life on ,land4 ,by ,prof4 ,f4 ,o4 ,bower1 ,sc4,d41 ,f4,r4,s4 ,links with the ,past in the ,plant-,world4 ,by ,prof4 ,a4 ,c4 ,seward4 ,,physics ,the ,earth4 ,by ,prof4 ,j4 ,h4 ,poynting1 ,f4,r4,s4 ,the ,atmosphere4 ,by ,a4 ,j4 ,berry1 ,m4,a4 ,the ,physical ,basis of ,music4 ,by ,a4 ,wood1 ,m4,a4 ,,psychology ,an ,introduction to ,experimental ,psychology4 ,by ,dr ,c4 ,s4 ,myers4 ,the ,psychology of ,insanity4 ,by ,bernard ,hart1 ,m4,d4 ,,industrial ,,and ,,mechanical ,,science ,the ,modern ,locomotive4 ,by ,c4 ,edgar ,allen1 ,a4,m4,i4,mech4,e4 ,the ,modern ,warship4 ,by ,e4 ,l4 ,attwood4 ,aerial ,locomotion4 ,by ,e4 ,h4 ,harper1 ,m4,a41 and ,allan ,e4 ,ferguson1 ,b4,sc4 ,electricity in ,locomotion4 ,by ,a4 ,g4 ,whyte1 ,b4,sc4 ,the ,story of a ,loaf of ,bread4 ,by ,prof4 ,t4 ,b4 ,wood1 ,m4,a4 ,brewing4 ,by ,a4 ,chaston ,chapman1 ,f4,i4,c4 ,,some ,,volumes ,,in ,,preparation ,,history ,,and ,,archaeology ,the ,aryans4 ,by ,prof4 ,m4 ,winternitz4 ,the ,peoples of ,india4 ,by ,j4 ,d4 ,anderson4 ,prehistoric ,britain4 ,by ,l4 ,mc,l4 ,mann4 ,the ,balkan ,peoples4 ,by ,j4 ,d4 ,bourchier4 ,the ,evolution of ,japan4 ,by ,prof4 ,j4 ,h4 ,longford4 ,the ,west ,indies4 ,by ,sir ,daniel ,morris1 ,k4,c4,m4,g4 ,the ,royal ,navy4 ,by ,john ,leyland4 ,gypsies4 ,by ,john ,sampson4 ,english ,monasteries4 ,by ,a4 ,h4 ,thompson1 ,m4,a4 ,a ,grammar of ,heraldry4 ,by ,w4 ,h4 ,st ,john ,hope1 ,litt4,d4 ,celtic ,art4 ,by ,joseph ,anderson1 ,,ll4,d4 ,,literary ,,history ,the ,book4 ,by ,h4 ,g4 ,aldis1 ,m4,a4 ,pantomime4 ,by ,d4 ,l4 ,murray4 ,folk ,song and ,dance4 ,by ,miss ,neal and ,f4 ,kitson4 ,,philosophy ,,and ,,religion ,the ,moral and ,political ,ideas of ,plato4 ,by ,mrs ,a4 ,m4 ,adam4 ,the ,beautiful4 ,by ,vernon ,lee4 ,,economics ,the ,theory of ,money4 ,by ,d4 ,a4 ,barker4 ,women's ,work4 ,by ,miss ,constance ,smith4 ,,education ,german ,school ,education4 ,by ,prof4 ,k4 ,h4 ,breul1 ,litt4,d4 ,the ,old ,grammar ,schools4 ,by ,prof4 ,foster ,watson4 ,,physics ,beyond the ,atom4 ,by ,prof4 ,j4 ,cox4 ,the ,sun4 ,by ,prof4 ,r4 ,a4 ,sampson4 ,wireless ,telegraphy4 ,by ,c4 ,l4 ,fortescue1 ,m4,a4 ,rntgen ,rays4 ,by ,prof4 ,w4 ,h4 ,bragg1 ,f4,r4,s4 ,,biology ,bees and ,wasps4 ,by ,o4 ,h4 ,latter1 ,m4,a4 ,the ,life-story of ,insects4 ,by ,prof4 ,g4 ,h4 ,carpenter4 ,the ,wanderings of ,animals4 ,by ,h4 ,f4 ,gadow1 ,m4,a41 ,f4,r4,s4 ,,geology ,submerged ,forests4 ,by ,clement ,reid1 ,f4,r4,s4 ,coast ,erosion4 ,by ,prof4 ,t4 ,j4 ,jehu4 ,,industrial ,,and ,,mechanical ,,science ,coal ,mining4 ,by ,t4 ,c4 ,cantrill4 ,leather4 ,by ,prof4 ,h4 ,r4 ,procter4 ,cambridge ,university ,press ,c4 ,f4 ,clay1 ,manager ,london3 ,fetter ,lane1 ,e4,c4 ,edinburgh3 #ajj1 ,princes ,street ,transcriber's ,note3 ,page #aa1 #ab4 8,olland0 defined in #ahfc by ,john ,morton thus3 ,olland 7,nors41 ,suff47 arable land which has been laid down to clover or grass1 for two years4 ,inconsistent spelling and hyphenation are as in the original4