184 LOUIS PASTEUR. 



demonstrated lactic fermentation, like alcoholic fer- 

 mentation, to be the work of a living ferment ; in 

 1861 he had discovered that the agent of butyric 

 fermentation consisted of little moving thread-like 

 bodies, of dimensions similar to those of the filaments 

 discovered by Davaine and Eayer in the blood of 

 splenic fever patients; in 1861 he had announced 

 that no ammoniacal urine existed without the pre- 

 sence of a microscopic organism ; in 1863 he had 

 established that the bodies of animals in full health 

 are sealed against the introduction of the germs of 

 microscopic organisms; that blood drawn with suf- 

 ficient precaution from the veins and the arteries, 

 and urine taken direct from the bladder, could be 

 exposed to the contact of pure air without putre- 

 faction, and without the appearance of living thread- 

 like organisms of any kind whatever, mobile or 

 immobile. It was all these facts which in 1863 

 brought back the attention of Davaine, as he himself 

 has acknowledged, to the observation which he had 

 made in 1850. 



' M. Pasteur,' said M. Davaine in a communication 

 made to the Academy of Sciences, 'published some 

 time ago a remarkable memoir on butyric fermenta- 

 tion, which consists of little cylindrical rods, possess- 

 ing all the characteristics of vibrios or of bacteria. 

 The thread-like corpuscles which in 1850 I saw in the 

 blood of sheep attacked with sang-dc-ratc, having 



