FOODS — HUMAN NUTRITION. 465 



"The data herein presented lead to the conclusion that in the carnivora 

 larger amounts of caffein are demethylated than in the herblvora, and that 

 the resistance to caffein is inversely as demethylation, since it has been shown 

 that caffein is much more toxic for carnivora than herbivora. The mechanism 

 of demethylation is in all probability utilized in the body as a means of defense 

 against the deleterious action of caffein, being more active in organisms for 

 which the drug is more toxic." 



A bibliography is appended. 



Studies on water drinking. — XIII, Hydrogen ion concentration of feces, 

 P. E. Howe and P. B. Hawk (Jour. Biol. Cliem-., 11 {1912), 'So. 2, pp. 129- 

 14O). — The hydrogen concentration of the feces of 2 men was determined in a 

 water drinking experiment, and of l*man in a fasting experiment, with the 

 usual preliminary and final periods. 



" The reaction of the feces was uniformly alkaline, the hydrogen ion concen- 

 tration varying between 0.15X10-8 and 9.8 XIO-^. As the result, of water 

 drinking with meals there was a tendency for the hydrogen ion concentration 

 to increase. Pronounced changes in the dietary regime, such as high protein, 

 low protein and fasting, did not affect the hydrogen ion concentration of the 

 feces sufficiently to cause other than small variations in the uniformly alka- 

 line reaction. As the result of fasting, the stools were alkaline in reaction 

 (hydrogen ion concentration of 1.4 XIO-^ and 0.94 XIO-^) as opposed to the 

 acid stools reported by previous investigators. The hydrogen ion concentra- 

 tion differs for the feces of different individuals living on the same diet." 



Earlier work has been previously noted (E. S. R., 27, p. 16S). 



Fasting studies. — VI. Distribution of nitrogen during a fast of one hun- 

 dred and seventeen days, P. E. Howe, H. A. Mattill, and P. B. Hawk (Jour. 

 Biol. Chem., 11 (1912), So. 2, pp. 103-127, fig. i).— In general, the percentage 

 of nitrogen distribution was similar to that reported by the authors in con- 

 nection with shorter fasting studies with dogs (E. S. R., 26, p. 360). 



Fasting studies. — VII, The putrefaction processes in the intestine of a man 

 during fasting and during subsequent periods of low and high protein 

 ingestion, C. P. Sherwin and P. B. Hawk (Jour. Biol. Chem., 11 (1912), No. 

 3, pp. 169-177). — Continuing the above experiments, the present investigation 

 was conducted with a normal man weighing 76 kg. to study the influence of 

 fasting, and a subsequent feeding of low and high protein diets upon the course 

 of intestinal putrefaction. The authors summarize the work as follows : 



" Intestinal putrefaction as measured by the output of urinary indican was 

 markedly decreased during the fasting interval. The seventh fasting day 

 showed an indican excretion amounting to 13.7 mg. as against an output of 60.5 

 mg. for the second fasting day. During the postfasting interval of low protein 

 ingestion jnitref action was increased in a very pronounced manner, the indican 

 values rising far above those obtained during the normal period preceding the 

 fast. The average daily indican output was but slightly higher during the 

 period of high protein ingestion than during the low period. 



" The indican data for the preliminary period, when taken into consideration 

 in connection with other similar data collected previous to certain tests upon 

 the influence of a high water ingestion, furnish an important verification of a 

 conclusion previously reported from this laboratory to the effect that ' the drink- 

 ing of copious or moderate volumes of water with meals decreases intestinal 

 putrefaction as measured by the urinary indican output.' 



" It was demonstrated that intestinal putrefaction was 50 per cent greater 

 when but 5.23 gm. of nitrogen was passed into the gastro-intestinal tract after 

 the fast than it was when 21.86 gm. of nitrogen was ingested before the fast. 



