lxxvi REPORT — 1877. 



But while we thus speculate on the first appearance of organized bodies in 

 nature, we ought to keep in mind that we are equally ignorant of the mode 

 of origin of the inorganic elements and their compounds ; and we may 

 therefore be excused if we suspend all theory and conjecture until we shall 

 be guided to more reliable hypotheses through the plain track of observation 

 and experiment. 



The practical applications of the increased knowledge of the origin of 

 minute animal and vegetable organisms are so numerous that it would 

 occupy a much longer time than is at my disposal to give any detailed account 

 of them ; but they are of such immense importance in their commercial, 

 social, and sanitary relations that they ought never to be lost sight of. 



It is now proved beyond doubt that the origin of putrefaction and fermen- 

 tation is dependent on the presence in the substances which are the seat of 

 change in these processes, or in the surrounding air, of the gerrns of minute 

 organisms of an animal or vegetable nature, and that the maintenance of the 

 chemical changes in which these processes mainly consist is coincident with 

 and casually (if not essentially) dependent upon the growth and multiplica- 

 tion of these organisms. 



Professor Lister had the merit of being the first to apply the germ theory 

 of putrefaction to explain the formation of putrid matters in the living body ; 

 and he has founded on this theory the now well-known antiseptic treatment 

 of wounds, the importance of which it would be difficult to overestimate. 



The success or failure of plans for the preservation of meat and other 

 articles of food without question depends on the possibility of the complete 

 exclusion of the germs which are the cause of putrefaction and fermenta- 

 tion ; and the management of such plans must therefore be founded on the 

 most accurate knowledge of these organisms, and the circumstances influenc- 

 ing the persistence of their vitality and the vigour of their growth. 



The theory of Biogenesis has also lately been the guide in the investigation 

 of the causes of various forms of disease, both in the lower animals and in 

 man, with the result of showing that in many of them the infective substance 

 consists, in all probability, of germs of minute animal or vegetable organisms. 



There is very great probability, indeed, that all the Zymotic diseases (by 

 which we understand the various forms of fevers) have their origin in germs. 

 As has been well remarked by Baxter in an able paper on " The Action of 

 Disinfectants," the analogies of action of contagiaare similar to those of septic 

 organisms, not to processes simply of oxidation or deoxidation. These orga- 

 nisms, studied in suitable fluids, multiply indefinitely when introduced in all 

 but infinitesimal proportions. Thus they are, as near as we can perceive, the 

 very essence of contagia*. 



* For the most interesting information on this subject, I cannot do better than refer to 

 the very able Papers by Dr. Burdon Sanderson in the ' Eeports of the Medical Officer 

 of the Privy Council,' 1873, 1874, and 1875. 



