THE BEGINNINGS OF LIFE. 181 



general doctrine concerning heterogeny. He says l : 

 c lt may be considered as a fundamental law that pheno- 

 mena of fermentation, or of catalytic decomposition, 

 precede or accompany every spontaneous generation . . . 

 Organisms are only produced from expiring nature itself, 

 and at the moment when the elements of the beings 

 upon which they are engendered enter into new chemical 

 combinations, and undergo all the phenomena of fer- 

 mentation and putrefaction 2 .... It thence results that 

 primary generations are only manifested after the bodies 

 from which they are derived begin to undergo the 

 initial stages of decomposition ; as if the new beings, to 

 become organized, awaited the disintegration of others, 

 in order that they might avail themselves of the 

 molecules of the dying organism as soon as these were 

 set at liberty.' Thus, then, under the sway of fermen- 

 tation or of putrefaction, c the organic molecules of 

 organized beings are decomposed and separated j and, 

 after having wandered at liberty during an unlimited 

 time, whenever les drconstances piastres begin to mani- 

 fest themselves, these molecules group themselves afresh 

 in order to constitute a new being 3 .' 



1 ' Heterogenie,' Paris, 1859, p. 335. 



2 Ibid. p. 136. 



3 But M. Pouchet did not range himself with Lamarck and others, 

 who believed that physical forces alone were capable of bringing about 

 Life and organization in dead inorganic matter; on the contrary, he 

 professed his belief in the activity of ' une force plastique,' or special 

 ' force vitale.' He says : ' Si dans nos experiences, c'est au contact de 

 corps divers que se developpent les Proto-organismes, il ne faut pas. 



