MODERN DEVELOPMENTS OF HIRVEY's WORK. 477 



a disease by supplying' a ferment from a solid nonglandular organ of tlie 

 body was, I believe, made in Harvey's own liospital by the use of raw 

 meat in diabetes.' It was not, however, until Brown-Sequard recom- 

 mended the use of testicular extract that the attention of the profession 

 became attracted to the use of extracts of solid organs. Since then 

 extract of thyroid, extract of kidney, extract of supra renal capsule have 

 been employed; but even yet they are only upon their trial, and the 

 limits of their utility have not yet been definitely ascertained. 



But yet another therapeutic method has been recently introduced 

 which bids fair to be of the utmost importance, the treatment of dis- 

 ease by antitoxins. The discovery by Pasteur of the dependence of 

 many diseases upon the presence of mihute organisms may be ranked 

 with that of Harvey, both in regard to the far-reaching benefits which 

 it has conferred upon mankind and for the simplicity of its origin. The 

 germ of all his discoveries was the attempt to answer the apparently 

 useless question, "Why does a crystal of tartaric acid sometimes 

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

 sprung 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 then- structure and 

 place in nature, appear in some respects to resemble him in the proc- 

 esses 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 coni- 

 ])aratively inert, they produce carbonic acid and alcohol, both of which 

 have' a powerful physiological action. From inert albumen they pro- 

 duce albumoses having a most powerful toxic action, and to the poi- 

 sonous properties of these substances att-^ntion was for a while alone 

 directed. But it would appear that at the same time they produce 

 poisons they also form antidotes, and when cultivated without the body 

 and introduced into the living organism they give rise to the produc- 

 tion of these antidotes in still greater quantity. 



The plan of protection from infective diseases which was first 

 employed by Jenner in smallpox is now being extended to many other 

 diseases, and the protective substances which are formed in th'? body 

 and their mode of action are being carefully investigated. The intro- 

 duction either of 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 protec- 

 tion or cure. By the use of antitoxins tetanus and diphtheria appear 

 to be deprived of much of their terrible power. But it seems probable 

 that a similar result may be obtained by the introduction of certain 

 tissue juices into the general circulation. It was shown by Wooldridge 

 that thyroid juice has a power of destroying anthrax ]>oison, and it 

 seems probable that increase of the circulation of certain organs will 



' Cf. Nature, 1893, Vol. XLIX, 121. 



