78 THE VITAMINES 



of bacteria. Upon reading through his work, one receives the 

 impression that although the animals ate more food than the controls, 

 they weighed much less, and soon died. The longest duration of life 

 was 40 days (204). Schottelius (205), criticising the above work, 

 expressed the idea that Cohendy's experiments showed, on the con- 

 trary, that the intestinal bacteria were useful, or even indispensable. 

 Such experiments were likewise carried out with mammals. 

 Kiister (206), working with goats, was able to maintain young 

 animals in a sterile condition for 35 days, during which time no 

 difference from the controls was noted. It is not impossible that 

 these experiments did not last long enough. Charrin and Guille- 

 monat (207) carried out similar experiments on guinea pigs, while 

 Kianizin (208) used guinea pigs and rabbits. The latter made his 

 animals breathe sterilized air and eat sterilized food. The poor 

 results of this regime were noticeable in from 4 to 9 days; the animals 

 suffered from weakness and died soon thereafter. Nutall and Thier- 

 felder (209) conducted the well known experiments on guinea pigs 

 in which these animals were kept free from bacteria and symptoms 

 of sickness and even showed a gain in weight. In this case, too,the 

 experiments were of rather short duration. 



These experiments required corroboration from the viewpoint of 

 progress in vitamine research. This view is held likewise by Weill 

 and Mouriquand (210) and Schaeffer (211). It must be pointed 

 out that while all the investigators working on the problem of bac- 

 teria-free existence thought that they were dealing with only a 

 single unknown factor (the role of bacteria), there were really two 

 to be considered. During the process of food sterilization, the 

 vitamines according to the choice of food and the conditions of 

 temperature were more or less affected by the heat, and probably 

 destroyed. It is obvious, therefore, that the problem of a germ- 

 free existence was much more complicated than was imagined by the 

 above mentioned investigators. From the facts known at present, 

 we may conclude that in some animals, in which it is not possible to 

 produce an avitaminosis by means of a diet either poor or lacking in 

 vitamines, the bacterial intestinal flora possibly assume the task of 

 preparing the necessary substances for the host. To solve the ques- 

 tion beyond all doubt, it is necessary to proceed so, that in the 

 first place we arrange for a bacteria-free growth; if this should fail, 

 the animals may perhaps be saved through the addition of vita- 



