370 LOUIS PASTEUR 



substance might undergo various modifications in contact 

 with air, so as to become successively alcoholic, lactic, butyric, 

 and other ferments. There is nothing more convenient than 

 purely hypothetical theories, theories which are not the 

 necessary consequences of facts; when fresh facts which 

 cannot be reconciled with the original hypothesis are dis- 

 covered, new hypotheses can be tacked on to the old ones. 

 This is exactly what Liebig and Fremy have done, each in his 

 turn, under the pressure of our studies, commenced in 1857. 

 In 1864 Fremy devised the theory of hemi-organism, which 

 meant nothing more than that he gave up Liebig's theory of 

 1843, together with the additions which Boutron and he had 

 made to it in 1846; in other words, he abandoned the idea of 

 albuminous substances being ferments, to take up another 

 idea, that albuminous substances in contact with air are pe- 

 culiarly adapted to undergo organization into new beings 

 that is, the living ferments which we had discovered and 

 that the ferments of beer and of the grape have a common 

 origin. 



This theory of hemi-organism was word for word the 

 antiquated opinion of Turpin. * * * The public, especially 

 a certain section of the public did not go very deeply into 

 an examination of the subject. It was the period when the 

 doctrine of spontaneous generation was being discussed with 

 much warmth. The new word hemi-organism, which was the 

 only novelty in M. Fremy's theory, deceived people. It was 

 thought that M. Fremy had really discovered the solution 

 of the question of the day. It is true that it was rather dif- 

 ficult to understand the process by which an albuminoua 

 substance could become all at once a living and budding 

 cell. This difficulty was solved by M. Fremy, who declared 

 that it was the result of some power that was not yet under- 

 stood, the power of "organic impulse."* 



Liebig, who, as well as M. Fremy, was compelled to 

 renounce his original opinions concerning the nature of fer- 

 ments, devised the following obscure theory (Memoir by 

 Liebig, 1870, already cited) : 



" There seems to be no doubt as to the part which the 

 vegetable organism plays in the phenomenon of fermentation 



FUMY. Comptes rvttdiu d* tAcad&mit, vol. hriii., p. 1065, 1864. 







