20 ANNUAL ADDRESS, MDCCCLXXI. 



busied themselves in endeavours to determine the precise 

 form of organic being concerned in the production and 

 dissemination of various diseases, and foremost among 

 these of cholera ; but I must confess that, to my mind, 

 these attempts at identification of the offending particles 

 have not succeeded. However, even admitting such failure, 

 the hypothesis of the agency of minute germs in the pro- 

 pagation of disease may still be upheld. 



References to authorities and quotations on this question 

 would be out of place here, and so I proceed to remark, 

 that the notion of the direct relation between disease and 

 organic germs of disease is favoured by the analogy of 

 admitted facts. Fermentation and putrefaction, although 

 in general aspect chemical processes, are certainly asso- 

 ciated with the presence of definite organisms in the mat- 

 ters undergoing those processes : moreover, there are cer- 

 tain diseases of the skin and of the hair dependent upon 

 the introduction and growth of forms of vegetable life. 



The illustrations I have borrowed from medical literature 

 of the part played by the minutest forms of life in the 

 economy of our race, and not I may add of that only, 

 but also in that of all other animals and likewise of 

 plants, might require apology, as being of too professional 

 a character, were they not so much to the purpose. 

 However, I will now briefly notice the influence of the 

 microscopic denizens of water in their relation to the pro- 

 cessess of nature now obtaining, as well as to those 

 prevailing in past time. 



True it is that "death and decay in all around we 

 see," but nevertheless they eventuate in new life. Animal 

 life exists as a posterior event to vegetable life and is 



