148 HUGH GLASGOW. 



instead of increasing in weight, their animals must have been 

 actually starving because unable in the absence of the proper 

 intestinal bacteria to digest the food swallowed. 



Pasteur's hypothesis as to the function of intestinal bacteria 

 was, a few years later, again tested experimentally by Schottelius, 

 who, after carrying out a carefully planned series of experiments, 

 arrived at conclusions decidedly different from those of Nut tall 

 and Thierfelder. 



In the experiments of Schottelius chickens were used instead 

 of guinea pigs. The artificially incubated eggs were removed 

 and carefully sterilized shortly before the time for hatching and 

 placed for hatching in a specially constructed, sterilized cage, 

 together with sufficient sterile food and water to last throughout 

 the course of the experiment. It was found that chicks hatched 

 and reared in this way, with the total exclusion of bacteria, 

 showed but very little growth; and while they continued to 

 eat ravenously, being apparently unable to satisfy their hunger, 

 they gradually became weaker 'and after an apparent slight 

 increase for the first few days invariably died, usually within 

 twenty-five days or less after hatching. 



In the control cages, which contained chicks treated in exactly 

 the same way except for the addition of a pure culture of a colon 

 bacillus to the food, the young animals developed normally in 

 every way and even appeared to show slightly better growth than 

 chicks of the same age which had been allowed to run free in 

 the laboratory as a counter check. 



These results are regarded by the author as showing conclu- 

 sively that intestinal bacteria, especially of the Bacillus coli 

 type, are absolutely essential to proper digestion in chickens and 

 that they doubtless have a similar function in other animals. 

 He summarizes as follows the precise manner in which he thinks 

 the normal bacteria influence the host: 



"i. Die Darmbakterien sind notwendig fiir die Ernahrung 

 der Wirbeltiere und fiir den Menschen; 



:< 2. Der Nutzen der normalen Darmbakterien besteht: (a) in 

 der Vorbereitung der Ingesta fiir die Resorption der Nahrungs- 

 stoffe; (&) in der Reizung der Darmw~nd zur Auslosung der 

 Peristaltik; (c) in der Uberwucherung und Vermichtung patho- 



