CONDITIONS FAVOTJEING FEBMENTATIOIf. 85 



But all similar grounds for reserve are absent — are non-existent, 

 in fact — in regard to the bearing of tbis experiment upon the 

 possibility of an occasional independent origin for zymotic disease, 

 wbether or not sucb disease is characterized by the appearance 

 within the body of any distinctive living organisms*. 



This I will now endeavour to demonstrate. 



It is the process of fermentation which is supposed to be in part 

 analogous to the zymotic disease. It is true that a contagious 

 something becomes engendered during fermentation and during 

 zymosis, by means of which the process or the disease may be 

 spread abroad. But there are important differences in regard to 

 the possible independent origin of the two processes which have 

 hitherto been only too much neglected. The treatment of this 

 subject has often been much too superficial. In order to produce a 

 kind of pictorial effect which may easily captivate the imagination, 

 difficulties are often ignored, and many new, modifying, or antago- 

 nistic points of view have even of late been treated as though they 

 were non-existent. 



A few words will suffice to make plain some of the differences 

 between the respective conditions which would be operative in 

 the germless origin of fermentation on the one hand, and in the 

 de novo origin of a contagious disease on the other. And in so 

 doing I shall be able, I think, at the same time, to show how much 

 simpler it would be to bring about an independent zymosis than 

 an independent fermentation — that is, if we are to rely on the 

 analogy upon which the germ-theorists base their arguments. 



During the great majority of fermentations living organisms 

 make their appearance and rapidly multiply. These living organ- 

 isms have been proved to be common producers of chemical prin- 

 ciples, some of which are soluble ferments, others (like pyro- 

 gen) are poisons which may be almost as deadly as that of a ser- 

 pent, whilst others still are inert and appear as mere pigment- 

 granules. It is proved that some of these chemical principles act 

 as true ferments f- It is thought, and it is probable, that the organ- 

 isms themselves — altogether apart from their media and what else 

 they may contain — may be capable of doing the same. Still this 

 has not yet been definitely proved ; so that the action of soluble 



* The rule is, that oi'ganisms are present in fermentations, whilst they are, 

 60 far as we know, quite exceptional in zymotic diseases, 

 t Pasteur, ' Compt. Eend.' July 3, 1876, p. 4. 



