III. 



THE ORGANISMS OF FERMENTATION. 



22. The Position of the Organisms in the 

 Botanical System. 



THE study of Mycology, or the science of Fungi, can be pur- 

 sued from several standpoints. The purely scientific position is 

 assumed by the botanist, who accords to each kind just as much 

 importance as its morphological and physiological considerations 

 warrant. If, however, the standard of interest adopted be that of 

 the importance of the part played by the fungi in practical life 

 i.e. Applied Mycology then the number of species to be studied 

 is reduced in a very gratifying manner. The degree of attention 

 bestowable on those remaining is determined, not by their syste- 

 matic position, but by the influence they exert on their environ- 

 ment, the nutrient medium. 



If the object subjected to the influence of the fungi is a living 

 creature, i.e. an animal or a plant, it is thereby brought into the 

 condition universally known as diseased. Fungi endowed with 

 this power are designated pathogenic, and their study is entitled 

 Pathogenic Mycology, which is subdivided into two branches, 

 according to the natural classification of the infected organism. In 

 the case of human beings or animals, we have the study of Medico- 

 Pathological Mycology, and in the case of plants, Phyto-Patho- 

 logical Mycology. 



On the other hand, inanimate objects, such as milk, wort, 

 vinegar, manures, leather, indigo, &c., on which the influence of 

 the fungi is manifested by symptoms of decomposition, constitute 

 the subject of Technical Mycology, which differs from the patho- 

 logical branch in another characteristic, namely, in the nature of 

 the influence suffered by the object. Pathological Mycology is 

 exclusively concerned with pathogenic, and therefore noxious, 

 fungi, and its object is to bring about their exclusion and annihila- 

 tion. The aim of Technical Mycology is different, being to effect, 

 by the aid of fungi, useful decompositions and transformations 

 which, without the use of such living tools, could only be accom- 

 plished incompletely, or in a more roundabout and costly manner. 



It is, therefore, with the influence of the fungi on their en- 

 vironment, i.e. the manifestations of their vitality, that technical 

 mycology has to do. Hence it is principally the study of the vital 



27 



