CONDITIONS TAVOFKING FEEMENTATION. 75 



particles capable of generating a febrile illness resembling septi- 

 caemia, which the organism itself is unable to produce — and also 

 from the fact discovered by Musculus, and confirmed by Pasteur, 

 that a soluble ferment exists in fermenting urine, separable 

 therefrom, and which is capable of producing precisely the same 

 changes in this fluid as may be initiated by the living ferment 

 itself. 



Yet, relying principally upon this evidence of Koch, Prof. Cohn 

 postulates for the spores of hay-Bacilli a power of resisting pro- 

 longed and thorough desiccation. And although Koch says 

 distinctly that he found no evidence of a survival of power to 

 communicate the disease when he dealt with small fragments of 

 splenic-fever matter which had been dried, Cohn assumes that for 

 hay-Bacillus even separate spores, or spores in association with 

 very small particles of matter, may preserve their potency ; nay, 

 further, that the conduction of heat no longer takes its ordinary 

 course in regard to such particles — so that they may remain for 

 hours immersed in fluids at temperatures destructive to all other 

 visible forms of living matter. Before all these difficulties 1 may 

 perhaps be pardoned for saying that I am not ready to yield assent 

 to the popular view. Mere surmises and guesses must make way 

 for definite knowledge acquired by accurate and crucial experi- 

 mentation. But as yet there is nothing of this sort to support 

 the notion of the ability of the ferment-organisms to endure com- 

 plete desiccation, and that in this state they are able to resist for 

 a prolonged period the otherwise destructive influence of heated 

 fluids. 



A fatal lack of precision seems to have pervaded all attempts 

 which have yet been made to deal with the question of the ability 

 of organisms or their germs to resist desiccation. This lack of pre- 

 cision is seemingly due to the fact that the mind of the experi- 

 menter is generally to a great extent biased by the notion of the 

 impossibility of a generation de novo of living matter. Just as 

 we have previously seen Pasteur inoculating barren fluids with 

 organic debris &c. filtered from the air, and assuming that 

 the fertility which ensues must have been due to this matter con- 

 taining living germs, so, more recently, we find other experimen- 

 ters subjecting such matter and the organisms which it may con- 

 tain, or subjecting organisms and portions of the media in which 

 they have been flourishing, to desiccating influences, and invari- 

 ably attributing any supervening fermentation or disease which 



