580 EXPERIMENT STATION RECORD. 



formed in the intestines, are so nearly the same that we must conclude that they do 

 not indicate a greater degree of the putrefactive process in one or the other period. 

 In fact, the evidence of the experiment is that the dietaries in periods 1 and 2 are 

 physiologically identical, and, since the dietary in each instance was composed to 

 the extent of two-thirds of the breads described, the evidence of the experiment is 

 that the two breads are physiologically the same. 



"There are certain criticisms of this experiment well worth considering. The 

 point is raised that the metabolic nitrogen is not subtracted from the total nitrogen 

 of the feces, in other words, that the figures obtained represent not the actual diges- 

 tibility, but rather the availability, of the diet. It would be interesting to subtract 

 the metabolic nitrogen and obtain actual figures of digestibility, but that is not 

 usually attempted in such experiments, since the methods of determining the meta- 

 bolic nitrogen at present known are quite inaccurate. It is, after all, the gain to the 

 body in each period which Ave seek to establish, and that is, of course, indicated by 

 the availability, and not by the digestibility. 



"The question whether the diet was full and nutritious, including that of whether 

 the subject was in nitrogenous equilibrium, is nf)t to be given the same consideration 

 here as in metabolism experiments in Avhich the question of the balance of income 

 and outgo is all-important. Of course, the diet should contain a fair amount of food, 

 but no effort need be made to establish an equilibrium; on the contrary, to diminish 

 the monotony of a fixed diet, investigators usually administer a little less than suffi- 

 cient to establish an equilibrium. This does not put the subject in an unhealthy or 

 in any way abnormal state. In fact, individuals vary their diet in this way in every- 

 day life, and even some athletes, in training, for a time do precisely this thing to 

 attain perfect health. The body adapts itself to certain variations that we must 

 recognize as physiological, and the fact that to-day we eat less and to-morrow more 

 is not an evidence of ill health. 



"In conclusion, then, the evidence of these experiments is that food prepared by 

 the use of a so-called alum baking jDowder does not interfere with secretion in the 

 stomach; and, even when it makes up the major part of the diet, it is utilized by the 

 body in the same way and to the same extent as an acceptable control diet. The 

 investigation does not reveal any reason for believing such food at all injurious or 

 unwholesome." 



Concerning' the dig'estion of starch, in the mouth, and stomach of man, 

 MtJLLEK {Med. Woche, 1901, p. 80; Chein. Centbl., 1901, I, p. 6,37; ahs.ia Zischr. Uaier- 

 sucli. Nahr. u. Genussmil., 4 {1901), No. 13, p. 605). — Experiments by a method which 

 is described led to the following conclusions: When flour porridge and bread were 

 eaten, 50 to 100 per cent of the starch was found in the stomach in soluble form, 

 usually a short time after it was consumed. The effect of chewing on digestibility is 

 marked; that of acidity, slight. Saliva is only slightly inferior to pancreatic juice as 

 regards its power to digest starch. 



Strength from eating, B. McF,\nDEN {New York: Physical Culture Puhllsldng Co., 

 1901, pp. 194, fi'J- !)■ — This book, which is written from a A'egetarian standpoint, 

 contains statements of a general character, including some not in accord with the 

 views commonly accepted by phyiologists and physiological chemists. 



Investigations on the excretion of carbon dioxid during muscular labor, 

 J. E. Johansson {Skund. Arch. Phij^ioL, 11 {1901), No. 5-6, pp. 273-307, figs. 6').— An 

 apparatus of special construction for measuring positive, negative, and "static" work 

 is described, as well as a number of experiments in which the amount of work per- 

 formed and the carbon dioxid excreted were measured, the author himself being the 

 subject. 



The chemical composition of perspiration, W. Camerek (Z/.sv/r;-. Biol., 4/ {1901) , 

 No. 2,p}). S71-374) ■ — The composition is reported of perspiration induced in u young 

 man bv different sorts of baths. 



