THE GASTRO-INTESTINAL FLORA OF NORMAL INFANTS 597 



where putrefactive action is maximal. 1 The theoretical and practical 

 difficulties of acclimatizing a milk parasite in the intestinal tract 

 would suggest that a normal intestinal organism of the lactic-acid 

 type, as Bacillus acidophilus 2 (whose habitat is the large intestine), 

 would be theoretically more efficient in those cases where Bacterio- 

 therapy is indicated. 



Bromatherapy. The very direct and striking relation between 

 the nature of the food of bacteria and the character of their products 

 of metabolism has an important theoretical and practical application 

 in relation to intestinal bacteriology in health and disease. It has 

 been stated in another section that products of bacterial metabolism 

 harmful to the host may be classified as nitrogenous compounds 

 derived from proteins and protein derivatives, and non-nitrogenous 

 compounds derived from carbohydrates and fats. The former are 

 produced by bacteria acting upon proteins and their derivatives in 

 the absence of utilizable carbohydrates; the latter are formed by 

 bacteria which are utilizing carbohydrates or fats. Thus, the diph- 

 theria bacillus forms a powerful toxin in protein media, but does not 

 form toxin when available carbohydrate is added to the medium; 

 Bacillus coli forms indol in protein media, but does not form indol 

 when available carbohydrate is added to the medium. If these bac- 

 teria were developing in the intestinal tract at levels where a contin- 

 uous supply of caibohydrate could reach them it would be theoretically 

 possible to reduce or even prevent the formation of toxin or indol 

 respectively when utilizable carbohydrates are present. 



There are a number of intestinal conditions of bacterial causation 

 in which available evidence points strongly to the formation of pro- 

 ducts arising from the metabolism of protein or protein derivatives 

 by specific organisms as important etiological factors in the morbid 

 process. Thus cholera, bacillary dysentery, typhoid, paratyphoid and 

 many less acute infections are associated definitely with the develop- 

 ment of these organisms within the body and, to some degree at least, 

 at the expense of the body tissues. 



All of these organisms produce lactic and other acids when suitable 

 carbohydrates are available; the products of fermentation of these 

 bacteria, chiefly lactic and other acids, are almost certainly no more 

 harmful to the host than are those formed by Bacillus bulgaricus, 



1 Herter and Kendall, Jour. Biol. Chem., 1908, v, 293; Rahe, Jour., Inf. Dis., 1915, 

 xvi, 210. 



2 Rotch and Kendall, Am. Jour. Dis. of Children, 1911, ii, 30. 



