April 18, 1913] 



SCIENCE 



605 



adjust its protein catabolism to the protein 

 supply and that a sudden increase of protein 

 in food causes a quite immediate increase in 

 protein cleavage. This does not mean, however, 

 that an excess of protein causes tissue waste 

 because this increase in protein catabolism, 

 due to an increased protein supply, undoubt- 

 edly occurs at the expense of nitrogen com- 

 pounds that are still in a circulatory or labile 

 condition. 



There can be no disputing the fact that 

 " animal food requires a considerable quantity 

 of oxygen for its utilization " ! It is well es- 

 tablished, to be sure, that the amount of heat 

 liberated by the use in the body of a given 

 volume of oxygen is somewhat less for pro- 

 teins than for carbohydrates. In view of the 

 facts that oxygen consumption is practically 

 proportional to the amount of energy developed 

 and that all the nutrients require for their 

 oxidation in the body " a considerable quan- 

 tity of oxygen," the above statement seems to 

 be somewhat peculiar in form, to say the least. 



We are not told on what experimental evi- 

 dence it is asserted that proteins are required 

 for the production of nervous energy, nor is 

 the difference between nervous energy or any 

 other energy explained. 



To make the terms " fibrinogen " and 

 " casein " synonymous as the principal pro- 

 tein in milk is hardly excusable. Fibrinogen 

 is a term given to the mother substance of 

 fibrin. It is possible that the author had in 

 mind caseinogen, a name once proposed for 

 the casein of milk before coagulation. 



Starch, cereals and vegetables, when cooked 

 imperfectly, are characterized as " indigest- 

 ible " and we are told that a " vegetable pro- 

 tein is very imperfectly digested and ab- 

 sorbed." In the first instance, the term in- 

 digestible may be used in the popular sense, 

 difficult of digestion, for the author, in sev- 

 eral places, confuses the meaning of the terms 

 digestion and digestibility, but to state that a 

 vegetable protein is very imperfectly digested 

 and absorbed is, as a general statement, in 

 utter defiance of facts. The records of diges- 

 tion experiments with human foods show that 

 on the average between 80 and 90 per cent, of 



the protein of cereals, vegetables and fruit is 

 digested and absorbed. Vegetable proteins, 

 according to this author, " are mostly globu- 

 lins." The proteins of wheat flour, of which 

 we consume more perhaps than any other veg- 

 etable forms, consist chiefly of glutenin and 

 gliadin, neither of which is globulin. It does 

 not appear to be true that globulins predomi- 

 nate in other cereals. Legumin is made to re- 

 semble casein " in many of its chemical reac- 

 tions." We now know that the legumins are 

 globulins and they appear to have little simi- 

 larity to the principal protein of miUv. The 

 theory that by churning " the albuminous 

 envelopes of the fat globules of the cream are 

 broken and the fat particles are permitted to 

 commingle and form a solid mass " was aban- 

 doned long ago. Those who are making a 

 study of milk advance the theory that by ad- 

 sorption the fat globules cause a concentra- 

 tion of albuminous matter around them, but 

 the breaking of the envelope through the agi- 

 tation of the cream is now not accepted. The 

 statement that sodium chloride acts in the 

 blood as a solvent of the globulins would seem 

 to be somewhat precarious. 



In discussing cow's milk, the author informs 

 us that " after the first week, it is usually the 

 richest and remains about the same for 

 months, provided the animal's diet is uni- 

 form." The fact is, as shown by numerous 

 analyses of the milk of cows through the en- 

 tire period of lactation, the milk is the least 

 rich a few weeks after parturition and in- 

 creases in richness as the period of lactation 

 progresses, especially when there is a decrease 

 in the yield. It seems to be assumed that a 

 change in diet changes the composition of the 

 milk which, in the main, is contrary to the 

 results of extended observations. 



When the author enters the field of prac- 

 tical dietetics, he still seems to be subject to- 

 error. In dealing with the influence of the 

 diet upon the mother's milk, he gives a set of 

 rules which, in the light of recent observa- 

 tions, should be lightly regarded. For in- 

 stance, we are told that to increase the total 

 quantity of milk and to decrease the total solids, 

 there should be an increase in the proportion of 



