26 THE HARVEIAN ORITION, 1894. 



Another therapeutic method has been recently introduced 

 which bids fair to be of tlie utmost importance — viz., the treat- 

 ment of disease by antitoxins. The discovery by Pasteur of the 

 dependence of many diseases upon the presence of minute or- 

 ganisms may be ranked with that of Harvey, in regard both to 

 the far-reaching benefits which it has conferred upon mankind 

 and to tlie simplicity of its origin. The germ of all his dis- 

 coveries was the attempt to answer the apparently useless ques- 

 tion, " Why does a crystal of tartaric acid sometimes crystallise 

 in one form and sometimes in another ? " From this germ 

 sprang his discovery of the nature of yeast, and of those microbes 

 which originate fermentation, putrefaction and disease. 



These minute organisms, far removed from man as they are 

 in their structure and place in nature, appear in some respects 

 to resemble him in the processes of their growth and nutrition. 

 They seem, indeed, to have the power of splitting up inactive 

 bodies into substances having a great physiological or chemical 

 activity. From grape sugar, which is comparatively inert, they 

 produce carbonic acid and alcohol, both of which have a power- 

 ful physiological action. From inert albumen they produce 

 albumoses having a most powerful toxic action, and to the 

 poisonous properties of these substances attention was for a 

 while alone directed. But it would appear that at the same 

 jtime as they produce poisons they also form antidotes, and when 

 introduced into the living organism they give rise to the pro- 

 duction of these antidotes in still greater quantity than when 

 cultivated without the body. 



The plan of protection from infective diseases, which was first 

 employed by Jenner in small-pox, is now being extended to 

 many other diseases, and the protective substances which are 

 formed in the body, and their mode of action, are being care- 

 fully investigated. The introduction of either pathogenic 

 microbes or of toxic products appears to excite in the body a 

 process of tissue-change by which antitoxins are produced, and 

 these may be employed either for the purpose of protection or 

 cure. By the use of -antitoxins tetanus and diphtheria appear 

 to be depiived of their terrible power. 



But it, seems probable, that a similar result may be obtained 



