PATHOLOGICAL MYCOLOGY. 



CHAPTER I. 



INTRODUCTORY. 



General Aspects. 



1. Since the theory of spontaneous generation has been abandoned, 

 through the classic researches of Cagniard-Latour and Schwann 

 at the one extreme, and the more recent investigations of Pasteur, 

 Lister, and Koch at the other, the various groups of the organised 

 ferments have become endowed with an interest far greater than any 

 with which they might be invested from their merely biological aspect. 

 They have assumed an almost vital importance from the fact that many 

 of them are now believed to play a prominent part in the causation of 

 certain morbid conditions, both in plants and throughout the whole 

 animal world ; and they have come to be recognised as most im- 

 portant factors in such conditions, — factors which must be carefully 

 accounted for in our consideration of many pathological processes, 

 factors which have been studied closely in connection with certain 

 pathological and clinical phenomena, and which not only help to 

 explain these phenomena, but in some cases furnish the only reliable 

 explanation. That these organised ferments — or micro-organisms, as 

 they are termed — do occur in very intimate relation to certain infective 

 diseases has never been doubted, since the means of their recognition 

 have been at our command. A serious discussion has arisen, how- 

 ever, as to whether the presence of these micro-organisms is indica- 

 tive of a causal or a purely accidental relation between them and the 

 morbid phenomena which appear in their host. In no scientific 



A 



