2 PATHOLOGICAL MYCOLOGY. 



problem has the building of hypotheses on other than the basis of 

 exact observation been more discredited, and the principle more firmly 

 established that the only rational method of search for any cause is 

 the close scrutiny of effects, within the confines of which the cause 

 must necessarily be traced. It thus happens that this discussion has 

 been already limited in many directions by the results of careful 

 investigation of all the circumstances which occur in such cases ; and 

 it is now held to be indisputable that in certain forms of disease 

 micro-organisms do play the part of the exciting cause. It is of 

 paramount importance to note what have been the means employed 

 in attaining this result, and to inquire whether the same principles 

 applied to the investigation of other diseases in which micro-organisms 

 occur may not lead to a more distinct and accurate conception of 

 their real significance. In so doing it will be found necessary to 

 enter somewhat minutely into details connected with the vital 

 peculiarities of these lowly organised forms, and to describe in order 

 those methods of cultivation and observation which the experience 

 of specialists in this domain of science has pointed out as the 

 simplest and most effectual means of becoming acquainted with their 

 more important characteristics. 



True Position of the Subject. 



2. Hitherto the work has been carried on by experts only, and the 

 medical profession has been divided into two distinct, but equally 

 illogical, factions. There seems to be a general disposition on the 

 one hand to " pooh-pooh " the very name of micro-organism, whilst on 

 the other there is only too good an example of excessive zeal. The 

 former section scouts the notion of any connection, direct or indirect, 

 relative or absolute, between micro-organisms and disease, of what- 

 ever nature. The members of this section have usually had but 

 scant opportunity of studying the evidence now at our disposal, 

 and still less have they tried to settle the matter by a thorough 

 personal investigation. The whole matter is summed up by them 

 as a prevailing " medical fashion," and is cast aside as utterly un- 

 worthy of serious consideration. The second section, it is much to 

 be feared, has in great measure to answer for this antagonism. Its 



