THE BACTERIA OF THE . ALIMENTARY TRACT. 175 



they may even serve a good purpose, for young guinea- 

 pigs removed from the uterus by Caesarean section and 

 kept in sterile vessels, given sterile air to breathe and sterile 

 food to eat do not thrive as do animals from the same 

 litter, born under the same circumstances but raised in 

 ordinary air and on non-sterilized food. It was found that 

 the latter were uniformly better nourished, heavier, and 

 lived longer than the former. ScnoTTELius 1 has made simi- 

 lar experiments on chicks and has found that when kept 

 under absolutely sterile conditions these fowls in twelve 

 days increase only 25 percent in weight instead of 140 per- 

 cent, as do the control animals. 



1 Cited from KOHLBRUGGE: Centralbl. f. Bakt., 1901, XXX, Ite 

 Abth., p. 26. 





