LEO F. RETTGER 645 



bacteria, are largely determined by the nature of the food or substrate upon which 

 they subsist. Thus, in a medium containing utilizable nitrogenous substances and no 

 available carbohydrate, intensive nitrogenous metabolism takes place, with the for- 

 mation of ammonia, amino acids (including tryptophane), amines, indol, etc. 



In the presence of fermentable carbohydrate, however, the metabolism assumes 

 a different aspect and becomes essentially fermentative, the degree and exact nature 

 of this process depending largely on the amount and kind of sugar present. In such a 

 metabolic process the nitrogenous products (including the so-called "putrefactive") 

 are relatively few and small in amount. 



These conditions are in a large measure reproduced in the large intestine, though 

 many influences are brought to bear here which do not as yet admit of satisfactory 

 interpretation. 



As early as 1886 Miller and Ostweiler independently demonstrated that the in- 

 gestion of carbohydrates tends to decrease so-called "intestinal putrefaction." Kraus' 

 observed the same influence in dogs. Hirschler- concluded that particular carbohy- 

 drates, lactose, sucrose, dextrin, and starch exerted some inhibiting influence on the 

 type of decomposition in the intestine. Others, including Poehl and Winternitz,-' 

 claimed that milk causes a decrease in the amounts of undesirable products of protein 

 decomposition. These observations were confirmed by Herter^ and by Leva.^ A pro- 

 nounced decrease in ethereal sulphates of the urine and a shift in the flora toward the 

 aciduric type were noted by Herter and Kendall'' after milk and dextrose feeding. 

 Barker^ and Torrey^ reported changes in intestinal flora and favorable clinical results 

 as the result of administration of lactose to t^'phoid patients. 



Other investigators, among them Solukha' and Kopetski,'" concluded that lactose 

 will inhibit putrefaction, when fed by mouth. These claims were not confined, how- 

 ever, by various workers to one or two definite carbohydrates, and g'ucose, maltose, 

 and sucrose were included among the carbohydrates which were claimed to have a 

 more or less direct influence on intestinal putrefaction. Various investigators have 

 found a direct relationship of the intestinal flora to diet, as, for example, Weiss, 

 Settler, De Gasperi, Fischer, Wollstein, etc. 



Rettger and Horton" noted a marked simplification of the intestinal flora of white 

 rats following the administration of a diet consisting of starch, lard, protein- 

 free milk, and purified proteins, gram positive organisms of the L. acidophilus and 

 L. bijidics types constituting almost the entire flora. Hull and Rettger'- found that 



'Kraus, E.: Ztschr.f. phys. Chemie, 18, 167. 1894. 



^ Hirschler, A.: ibid., 10,306. 1S86. 3 winternitz, H.: ibid., 16, 460. 1892. 



^Herter, C. A.: Brit. M.J., 2, 1847. 1897. 



sLeva, J.: Berl. klin. Wclmsclir., 45, 922. 1908. 



'Herter, C. A., and Kendall, A. I.: /. Biol. Clieiii., 7, 203. 1909. 



'Barker, L. F.: J. A.M. A., 63,929. 1914. 



^Torrey, J. C: /. Infecl. Dis., 16, 72. 1915. 



' Solukha, I. P.: Dissertation. St. Petersburg, 1896. 



'"Kopetski, I. A.: Dissertation. St. Petersburg, 1900. 



" Rettger, L. F., and Horton, G. D.: Centralbl. f. Bakleriol., Abt. I, Orig., 73, 362. 1914. 



"'Hull, T. G., and Rettger, L. F.: ibid., 75, 219. 1914; /. Bad., 2, 47. 1917 



