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 pursued 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 physio- 

 logical 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 remain- 

 ing is determined, not by their systematic position, but by the influence they 

 exert on their environment, 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-Patho- 

 logical Mycology, and in the case of plants, Phyto-Pathological 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 pathological 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 annihilation. The aim of Tech- 

 nical Mycology is different, being to effect, by the aid of fungi, useful decom- 

 positions and transformations which, without the use of such living tools, 

 could only be accomplished incompletely, or in a more roundabout and costly 

 manner. 



It is, therefore, with the influence of the fungi on their environment, i.e. 

 the manifestations of their vitality, that technical mycology has to do. Hence 

 it is principally the study of the vital functions of ferments, and may therefore 

 be also termed Fermentation Physiology. With botanico- physiological con- 

 siderations it is concerned only in so far as they either afford assistance in the 

 comprehension of the physiology of the organisms, or facilitate the differentiation 

 of the various species from one another; and to this extent a knowledge of the 

 morphology of the fungi is of essential assistance to the technical mycologist in 

 the attainment of his objects. Before going more minutely into this matter, it 

 will, however, be advisable to have a general view of the position occupied by the 

 fungi in the botanical system. 



As every reader will be aware, the sub-kingdom Cryptogamia, which com- 

 prises all non-flowering plants, is divided into three chief sections, or seven 

 classes, viz. : 



