382 LECTURE XXIV. 



fonnation of lignite and turf. This enormous labour, however, is chiefly performed 

 by universally distributed Fungi, which not only absorb the materials necessary for 

 their nutrition, which would result in effects only extremely insignificant, but destroy 

 in addition the substances which they do not take up. We find this peculiar 

 destructive action taking place to the greatest extent by means of the Fungi of fer- 

 mentation and putrefaction in the narrower sense. That others also effect similar 

 work has already been mentioned above, in connection with the Fungi which destroy 

 wood ; and the mouldering and final disappearance of the masses of fallen autumn 

 leaves in woods must be ascribed to similar destructive actions of Fungi, the quantity 

 of Fungus produced itself remaining extremely insignificant. 



So far as the Fungi simply derive nutriment from their substratum, their nutrition 

 resembles in the main that of phanerogamic parasites and saprophytes; what 

 particularly distinguishes very numerous Fungi, however, is the decomposition of the 

 organic substratum as already mentioned, the products of the decomposition not being 

 taken up by the Fungus. Only in this way is it possible for Fungi to prevent the 

 continual accumulation of organic substances on the surface of the earth ; since if 

 they were to make use of their organic substratum only for the purposes of their 

 own nutrition, there would simply result an enormous accumulation of these plants. 



If we now attempt to obtain a more exact insight on the one hand into the 

 nutrition of the Fungi, and, on the other, into the destruction of their substratum 

 effected in addition by many of them — and thus into the nature of fermentation and 

 putrefaction — we shall find that the shortest way here, as in the case of the nutrition 

 of normal plants, is at once to make clear the results derived from the artificial 

 nutrition of Fungi, and the experimental study of the phenomena of fermentation. 



The first experimental investigations into the nutrition of Fungi were under- 

 taken by Pasteur about thirty years ago. I here pass over the methods of 

 cultivating Fungi, especially the highly organised forms, in decoctions of fruit and 

 dung, and in various mixtures of gelatine and sugar, etc., which have meanwhile been 

 much further developed, because in these methods of culture, highly important 

 as they are for the biology of the Fungi, it has only been sought to bring various 

 kinds of Fungi to normal development, in order to make clear their growth 

 and reproduction and the configuration of their relations of organisation; the 

 proper — i. e. the chemical — questions of nutrition not coming further into consider- 

 ation. Naegeli" (with the co-operation of Dr. Loew) has, however, recently made 

 some very detailed investigations and theoretical considerations on the matter. 

 Hence we shall obtain the desired glimpse into the processes of nutrition and 

 ferment action of the Fungi most quickly, if I shortly present the most important 

 results of Naegeli's work in this province. 



The Fungi, like other plants, require in addition to those compounds which 

 afford them the elements of the proteid substances, fats and carbo-hydrates— viz., 

 Carbon, Hydrogen, Oxygen, Nitrogen and Sulphur — also certain mineral matters, 

 the presence of which is necessary in the chemistry of nutrition and for the mole- 



• The works of Naegeli (and Loew) referred to are to be found in the Sitzungsber. der kgl. 

 bayr. Akad. under the title ' Emdhrung der niederen Pike' (1879), and ' ffber die Fettbildung dir 

 niederen Pilze' (1878). 



