694 ARTHUR ISAAC KENDALL 



only with respect to temperature [that of the body being 37.5 C., and 

 that of the outside world varying with climate and season], but also 

 in association with those purely intestinal factors of secretions, includ- 

 ing bile, enzymes and products of enzyme activity. These ancillary fac- 

 tors exercise a not immaterial influence upon prospective intestinal ten- 

 ants. It is significant, however, that notwithstanding these environmental 

 differences, the intestinal souring of milk is the qualitative equivalent 

 of the spontaneous souring outside of the human body. The significant 

 factor is the continuous availability of lactose in both processes. 



Experimental Evidence of the Effects of Sugars upon the Intestinal 

 Flora. Many studies upon experimental animals have shown the effects 

 of utilizable carbohydrates, as lactose, glucose, and other bioses, and 

 polysaccharids, upon the establishment of an intestinal flora in adult 

 animals and man. When such substances are added to the diet in suffi- 

 cient amounts to permeate the entire absorptive length of the alimentary 

 canal, the flora induced is the chemical replica of that of the normal 

 nursling. When the carbohydrates are reduced or eliminated from the 

 regimen, proteolytic bacteria rapidly gain the ascendency. 



Escherich appears to have been the first observer actually to per- 

 form dietary experiments upon animals. Dogs were selected. A four 

 weeks' old puppy was fed first upon milk, then upon meat. The changes 

 in the character of the excreta and of the bacteria in the excreta were 

 observed in each instance. A milk diet led to the evacuation of bright 

 yellowish dejecta, the consistency and odor of which were, reminiscent 

 of those characteristic of the normal nursling. The organisms detectable 

 were very similar to those of a normal nursling. 20 Gelatin-liquefying 

 bacteria were few in numbers, but coccal forms became more numerous. 

 The substitution of meat for milk induced a striking change in the 

 appearance of the feces, and in the character of the fecal bacteria. The 

 former lost their golden yellow color and became dark in color, smaller 

 in bulk, and possessed of a fecal odor, suggesting in this respect that 

 of a normal adult. Gelatin-liquefying bacteria increased very decidedly 

 in numbers and in activity. Coccal forms were relatively diminished. 

 Spores of proteolytic organisms, presumably of the mesentericus group, 

 became prominent in stained smears from the meat-diet feces, and the 

 entire picture, bacterial and chemical, so far as determinations were 

 possible, suggested that the entire intestinal condition induced was simi- 

 lar to that of normal adults. 



Following this monumental work of Escherich, which was so care- 

 fully carried out but unfortunately limited because of the meager fund 

 of bacterial knowledge and the lack of adequate chemical methods avail- 



20 It should be remembered that the dominant organism of the typical nursling's 

 feees Baci/lus bifidus was not known in Escherich's time. It was isolated nearly 

 fifteen years later (Tissier). 



