THE VITAL PHENOMENA OF BACTERIA. 57 



aerobically the obligatory anaerobic bacillus 

 of symptomatic anthrax. I have constrained, 

 on the other hand, the cholera germ to adopt an 

 anaerobic mode of life, and thereby arrived at 

 an explanation of its growth in the intestine 

 and the intestinal walls. 



It might be possible, in an extreme case, 

 to bring a microbe, ordinarily causing oxida- 

 tion, to such a point that, in the absence of 

 oxygen, it would even reduce from the oxides 

 the selfsame body, the power to oxidize which 

 was its first known peculiarity. For example, 

 the same microbes which, in the presence of 

 oxygen, oxidize ammonia to nitric acid might, 

 in the absence of oxygen, reduce the nitric 

 acid to ammonia. I have on hand at present 

 some unfinished experiments to test this possi- 

 bility. The determining cause in any event 

 lies in the grouping of the atoms in the mole- 

 cule which, either in the presence of oxygen 

 or in its absence, is torn apart by the disinte- 

 grating impulse. This molecular disintegra- 

 tion is not necessarily brought about only by 

 living things ; other forms of motion can ac- 

 complish the same result. Duclaux obtained 

 by insolation a sort of alcoholic fermentation 

 of sugar, and, according to Ritsert, light and 

 oxygen together effect an oxidation of fat. 



In the cultivation of anaerobes upon favor- 



