288 MICROBES, FERMENTS, AND MOULDS. 



These words were written more than thirty years 

 ago, and it may be asked whether the immense pro- 

 gress which science has made since that date has not 

 somewhat modified the author's opinions. Jousset 

 de Bellesme is scarcely entitled to take these words 

 and paraphrase them as follows : " The microbe, 

 where it really exists, is only a secondary phe- 

 nomenon, and it would not be too much to say that 

 no fresh element has intervened, either in small-pox, 

 scarlatina, or tubercular disease ; in such cases there 

 is only an exaggeration and reproduction of normal 

 elements, which, influenced by wholly obscure con- 

 ditions, are evolved in an altogether unusual manner." 



The definition given by Jousset de Bellesme is not 

 that of contagious diseases, but of those which are 

 combined under the generic name of cancer. If he 

 means to compare these diseases with cancer, such a 

 comparison is impossible. It is well known that 

 cancer is not contagious, and this fact alone places a 

 gulf between these two kinds of disease. Cancer is 

 not only not contagious nor is it conveyed by inocula- 

 tion, but it is only hereditary in about a tithe of 

 cases. Tuberculosis is, on the other hand, a con- 

 tagious disease, because it is produced by microbes, 

 and it may be set down as hereditary in nine cases 

 out of ten. 



Jousset de Bellesme's theory, therefore, explains 

 nothing, and leaves the question absolutely untouched, 

 since it throws no light on contagion and virulence, 



