644 BACTERIA OF THE INTESTINAL TRACT 



first to stimulate interest in the question as to whether life without bacteria is impossi- 

 ble, though he left the attempted solution of this problem to others. 



Nuttall and Thierfelder' in 1895 concluded, as the result of their observations on 

 guinea pigs, that intestinal bacteria are not necessary. Schottelius^ experimented with 

 chicks and arrived at the opposite conclusion. The observations of 0. MetchnikofT^ 

 on tadpoles supported the claims of Schottelius. 



On the other hand, E. Metchnikoff'' maintained that scorpions and certain worms 

 do not harbor intestinal bacteria, and that very few are found in the Indian bat. 

 Wollman^ experimented with flies which were obtained germ-free from sterilized eggs 

 and kept in sterile glass tubes, and showed that normal growth of the larvae took 

 place without bacteria. He was also successful in rearing tadpoles under aseptic con- 

 ditions. Cohendy*' repeated the experiments of Schottehus on chicks hatched from 

 sterilized eggs, and found that the chicks were in as good condition after two to six 

 weeks as the controls reared in the usual manner. 



Levin^ reported that the intestines of most of the polar animals examined by him 

 bacteriologically were free from bacteria. These claims were disputed by Chauveau 

 and others. 



Kiister^ removed a young goat aseptically by Caesarean section and kept it germ 

 free for fourteen days. The goat grew and remained normal. However, this same in- 

 vestigator^ states that intestinal bacteria are necessary for young animals, and also 

 perhaps for human adults and full-grown animals on account of their fermentative, 

 antagonistic, and physical actions. 



The question as to whether bacteria are necessary in the intestine is still an open 

 one. though the preponderance of evidence appears to support the view that they are 

 not essential. 



DIET AND INTESTINAL FLORA 



The term "intestinal putrefaction" has long been used more or less popularly to 

 designate changes which take place in the intestine through the action of micro-organ- 

 isms on the more complex nitrogenous substances in the large intestine, with the for- 

 mation of products which are at least mildly toxic and are in a large measure absorbed 

 from the intestine. Such a process has been described by some as one of "autoin- 

 toxication." 



Whether or not the use of these terms is strictly accurate, it has long been known 

 that different organisms can and do bring about the formation of products character- 

 istic of them, and that the activities of the different types, and indeed most types of 



' Nuttall, G., and Thierfelder, H.: Ztschr.f. phys. Cheinie, 21, 109. 1895. 



- Schottelius, M.: Arch.f. Hyg., 67, 177. 1908. 



3 Metchnikoff, O. : Ann. de Tlnst. Pasteur, 15,6^1. 1901. 



iMetchnikolT, E.: Ann. de I'lnst. Pasteur, 23, gi^j. igog; Prolongation of Life. New York, 1907. 



5 Wollman, E.: Ann. de rinsl. Pasteur, 24, 79. 1911; 27, 154. 1Q13. 



'' Cohendy, M.: ibid., p. jo6. 1912. 



7 Levin.: /6u/., 13, 55S. 1S99. 



* Kiister, Iv: Centiallil. f. Bakteriol., Abt. I, Beilage, 54, 55. 1913; Deutsihc mcd. Wchnsclir . 

 39. iS>^6. 1913. 



'Kiister, E.: Kolle and Wasscrniann, Ilandb. d. path. Mil^roorg., 6,468. 1913. 



