Semi-Centennial Volume. 107 



factor. Two flours may have the same percentage of alcohol-soluble 

 protein, but differ very greatly in baking qualities. In a series of mill 

 stream floui's, all made from the same wheat, the percentage of gliadin 

 will be higher in the better grades, but this is as far as the comparison 

 goes, so far as he knew. 



Professor Swanson thinks we shall have to work out the baking fac- 

 tors separately. For instance, a certain set of factors controls the ab- 

 sorptive capacity. Another set of factors controls loaf volume, another 

 what we may call adaptability for a variety of purposes. Then the prob- 

 lem is complicated by the fact that the same factor may enter into sev- 

 eral of the characteristics. He thinks that no progress will be made upon 

 these lines until we take up some of the fundamental pi'oblems. The de- 

 velopment of collodial chemistry ought to be a great help. The electro- 

 lytes are possibly of more fundamental importance than we have thought. 



However well a flour may be adapted for bread baking, so far as 

 physical qualities are concerned, its value in our dietary will depend en- 

 tirely upon the digestibility of the finished product. Accordingly ex- 

 periments have been made as to the comparative digestibility of breads, 

 using artificial digestion. The results show that one bread is as diges- 

 tible as the othei" — that of wheat flour alone, and that of the corn starch 

 mixture. It may be in place to state that any experiments, however 

 modest they may be, which contribute to the subject of wheat conserva- 

 tion at this time, are of interest, and if these point only to a line of work 

 which others more competent and better equipped may follow up to 

 some definite and practical conclusion, it would help to further the solu- 

 tion of the problem of food conservation. 



Recent experiments on nutrition have more clearly than ever em- 

 phasized the importance of mixed diet, and because of the bearing these 

 have it may be well to give a brief review of some of them in so far as 

 they may touch upon the subject in hand. In the first place, it may be 

 stated that dieticians are now making some fine distinctions as to what 

 is efficient and what is comparatively inert as food material, and we are 

 m.ore than interested in watching how these fine distinctions are em- 

 ployed. Furthermore, recent scientific investigations have shown that 

 the proteins of different foods are not alike, nor have they the same de- 

 gree of efficiency. Each food substance has what may be termed efficient 

 and deficient proteins. The gelatine of meat may be regarded as a de- 

 ficient protein, since it does not contain the full quota of amino-acids. 

 Another example of deficient protein is gliadin of wheat; still another 

 is zein of corn. All of these protein substances, however, yield nitrogen, 

 and by computation may show protein values, which may be misleading. 

 The fact seems to be that laboratory analysis is no indication of the real 

 merit of proteins. An examination of foods in the chemical laboratory 

 does not tell anything at all about their actual nutritive values. The 

 same ambiguity arises in feeding; if, for example, corn is fed with oats, 

 the results are better than if each were fed alone. 



We occasionally find a rather misleading comparison made between 

 the value of the protein of wheat and that of corn, by comparing in- 

 efficient zein with the glutelin of wheat. Although maize protein contains 

 zein in a large amount, the next most abundant protein, glutelin, of 



