348 



LECTURE XXI. 



alcohol, carbon dioxide, gl}-cerine, and succinic acid, and proteid matters are split up 

 by Bacteria into a long series of chemical compounds. But Naegeli, in his ' Theory 

 of Fermentation' (1879), has given sufficiently strong reasons for believing that the 

 fermentation and putrefaction due to the action of organised ferments are processes 



essentially different from 

 ordinary ferment actions. 

 Above all, Naegeli insists, 

 and rightly, that the hypo- 

 thetical ferment which the 

 ferment-fungi and putrefac- 

 tive fungi are supposed to 

 excrete has not yet been 

 extracted from the cells and 

 described. On the con- 

 trary, the cause which ef- 

 fects the fermentation is 

 inseparably connected with 

 the substance, and indeed 

 with the protoplasm of the 

 living cells of the Fungus. 



' Fermentation by means 

 of Fungi/ says Naegeli, 'only 

 takes place in immediate 

 contact with the protoplasm, 

 and so far as its molecular 

 action extends. If the or- 

 ganism needs to affect 

 chemical processes in areas 

 and at distances where it 

 is able to exert no power 

 by means of the molecular 

 forces of the living sub- 

 stance, it excretes ferments. 

 The latter are particularly 

 effective in the cavities of 

 the animal body, in the 

 water in which Fungi live, 

 and in vegetable cells poor 

 in protoplasm. It is even 

 very questionable whether 

 the organism ever forms 

 ferments which shall be ac- 

 tive within the protoplasm; since here it does not require them, much more energetic 

 means for chemical action being at its disposal in the molecular forces of the living 

 substance itself.' 



I find with Naegeli a further particularly striking point of difference in the fact 



Fig. 237.— Seedling of tlie Gourd, -w primarj' root ; « « lateral roots ; l> hypocotyl 

 (■cotyledons. At this time the cotyledons contain starch and sugar in addition t( 

 much fat : the same is also the case in the hypocotyl, less so in the root. The hypo 

 cotyl and root also contain fatty oil derived from the cotyledons. 



