CONDITIONS FAVOUBINa PEEMENTATION. 89 



cases, the independent organism does, so it is supposed that in the 

 process of zymosis tissue-elements may take on a specifically faulty- 

 action, leading to the formation of certain chemical principles or 

 " contagia " in the fluids or tissues of the animal body ; so that, 

 in the great majority of zymotic diseases, offcast particles from the 

 body, whether living or dead, when saturated with such principles, 

 mav constitute the veritable contagia by which the specific 

 disease is spread abroad amongst the community. 



In the majority of the cases of intracellular fermentation no 

 independent organisms are generated, though in others, as in that of 

 the beetroot and the potato, they are invariable concomitants. Simi- 

 larly in the majority of zymotic diseases no independent organisms 

 are generated, though in others, such as relapsing fever and splenic 

 fever, they are invariable concomitants ; and being engendered 

 in diseased parts and fluids they may thereafter themselves act 

 either as real contagia or as carriers of contagion. 



The causal conditions capable of inducing fermentation in the 

 beetroot and the potato, and with it the appearance of Bacteria 

 in swarms throughout their tissues, are known, and have no 

 ordinary connexion with preexisting Bacteria. And similarly 

 thecausal conditions capable of inducing relapsing fever and splenic 

 fever, though not so definitely known, may nevertheless have no 

 ordinary connexion with preexisting Spirilla and Bacilli resem- 

 bling those which appear in the blood or tissues of the patients 

 suffering from either of these diseases. 



Thus the mere fact that in certain zymotic diseases living 

 organisms have been proved to appear, affords of itself no support 

 whatever to an exclusive germ theory, as I shall, after this digres- 

 sion, endeavour to show. 



The fact may be quite otherwise explained, either (1) in accor- 

 dance with the views of certain germ-theorists, though these are 

 in direct opposition to the statements of others of the same party ; 

 (2) in accordance with the statements of this second section of 

 the germ-theorists, supplemented by a belief in heterogenesis. 



(1) The presence of latent germs of common though modifiable 

 ferment-organisms throughout the body is invoked by one section 

 of the germ-theorists, who contend that certain altered states of 

 health, together with altered vitality of tissues, may rouse such 

 hitherto latent common organisms into activity, and occasionally 

 convert them into so-called " specific " forms capable of new actions. 

 But based as this view is upon wholly insufficient evidence, and 



