OF THE NATURE OF THE CONTAGIOUS 

 DISEASE GERM. 



Contagious Disease Germs not Parasites. Many 

 different things, the characters of which are not very 

 clearly defined, and not to be easily determined, are 

 often called by the same name, and it is perhaps not 

 to be wondered at, considering the serious difficulties 

 encountered by scientific investigators in their attempts 

 to discover the real nature of the contagious disease 

 germ, that this virulent particle should, as it were, by 

 common consent, have received the reproachful desig- 

 nation, "parasite." But it is much easier to call a thing 

 a name, and to assert that it belongs to a particular 

 order or class of things, than it is to demonstrate its 

 affinities, and assign good and sufficient reasons for 

 the nomenclature and classification adopted. There 

 are some objections to the view of regarding disease 

 germs as parasites, which do not appear to have pre- 

 sented themselves to many of those who have used 

 the word. Some have indeed tried to give to it a 

 wider and more extended meaning than can be justi- 

 fied, and thus have included in the parasitic class many 

 living organisms that ought not to have been con- 

 signed to so questionable a position. 



The doctrine of the parasitic origin of contagious 

 disease has no doubt received some support from the 

 circumstance that certain morbid affections have 



