SAPEOPHYTES AND PAEASITES. 31 



The parasites proper may be divided into two groups : strict or 

 obligate parasites, which are restricted to living animals or vege- 

 table bodies, and facultative parasites, which will also thrive on 

 suitable inanimate substrata, and can therefore be cultivated on 

 artificial nutrient media. 



This latter group forms the connecting link between Patho- 

 logical and Technical Mycology. The former science regards these, 

 together with the obligate parasites, as the causes of disease, whilst 

 conversely Technical Mycology is interested in the facultative 

 parasites on account of the decompositions they induce in artificial 

 media, i.e. outside the animal or vegetable economy. This interest 

 is, however, purely scientific, since, for hygienic reasons, the use of 

 parasitic ferments for practical technical purposes is precluded. 



The true interest of the technicist in the domain of Mycology 

 is exclusively centred in the non-parasitic ferments, and these 

 alone form more especially the subject of the present work, the 

 first volume being devoted to the Schizomycetes, and the second 

 to the Eumycetes. 



