226 BIOLOGY AND TECHNIQUE 



to grow numerous, and in the cecum and colon, which are the seat 

 of the greatest bacterial activity, the flora consist chiefly of Colon 

 types, B. mesentericus, a few anaerobic spore formers of the Welch 

 bacillus type, and Gram-positive cocci. 



All who have studied this subject have found that diet has a 

 definite and important bearing upon the intestinal flora and that 

 definite changes may be brought about in the bacterial contents 

 of the bowel by purposefully adjusting the diet. The studies of 

 Herter 16 and of Kendall/ 4 particularly, have been contributed to 

 our knowledge of this subject. Herter has laid particular stress 

 upon the importance of the Welch bacillus and its subvarieties upon 

 intestinal putrefaction. In this he is not entirely in agreement with 

 Eettger 18 and others who believe that the Welch bacillus attacks 

 proteins but slightly, being chiefly concerned with carbohydrate 

 fermentation. Herter has produced indicanuria in dogs by feeding 

 large amounts of meat, and found that with such feeding the colon 

 and ileum contained considerable numbers of anaerobic bacilli. He 

 also believes that this bacillus is particularly concerned with a 

 chronic putrefactive activity which takes place in the large intes- 

 tine, in the course of which anaerobic bacilli produce butyric acid. 

 In consequence of this, there may be a considerable intestinal irrita- 

 tion and carbohydrate intolerance. Considerable anuria may also 

 be a consequence. Other writers like Friedman 19 believe that con- 

 stipation favors the increase of these putrefactive organisms. 

 Simonds 20 has made an exhaustive study of the relationship of the 

 Welch bacillus group to intestinal conditions, and has reviewed the 

 literature extensively. He summarizes his studies on this problem 

 as follows: "In the case of gas bacillus diarrhea, the presence of 

 an excess of carbohydrates in the intestinal content brings about 

 conditions in the lower ileum and first part of the colon which are 

 particularly conducive to the growth of B. Welchii. The absence 

 of lactic acid producing bacteria, as pointed out by Kendall, renders 

 conditions still more favorable to the multiplication of these or- 

 ganisms. They, therefore, rapidly increase in numbers, produce 

 irritating butyric acid, and are swept on in excessive numbers into 

 the lower bowel. The number of spores produced will be measurably 



18 Eettger, Jour, of Biol. Chem., 2, 1906, 71. 



10 Friedman, Transac. of Chicago Pathol. Soc., 1901, cited from Simonds. 



20 Simonds, Monograph of Rock. Institute, No. 5, 1915. 



