578 



VITAL ACTIONS OF THE LOWER FUNGI. 



bacteria,. 



Hum and aspergillus (not in mucor); and Bourquelot* 

 found in Aspergillus niger, a ferment which he was able 

 to extract, and which inverted maltose and cane-sugar. 

 The same ferment is also constantly, and in large 

 quantities, produced by the ordinary yeast, which can only 

 cause fermentation of cane-sugar by virtue of this ferment. 

 According to Kjeldahlf the invertin of yeast extract 

 does not act on maltose. The action on cane-sugar 

 occurs best between 53 and 56 C., and when the 

 reaction of the fluid is slightly acid. All the species of 

 yeast do not produce invertin; thus, EouxJ found a 

 small round torula, which caused intense fermentation 

 in solutions of glucose, but which was without action on 

 Occurrence in cane and milk sugar. Bacteria also not uncommonly 

 appear to have the power of inverting these substances ; 

 this is asserted to be the case by Hueppe, for example, 

 in the case of the bacillus of the lactic fermentation ; this 

 organism causes fermentation of cane and milk sugar 

 only after an alteration of the fluid as regards the invert- 

 ing property has occurred, which alteration is probably 

 caused by hydratisation. Bourquelot, on the other 

 hand, concludes from his experiments that the bacteria, 

 of the lactic fermentation can cause the fermentation of 

 maltose and cane-sugar directly and without preliminary 

 inversion. This contradiction is perhaps explained by 

 the circumstance that the two authors were not working; 

 with the same species of bacteria. In the case of th& 

 butyric acid bacilli, it is unanimously agreed that it does 

 not possess any inverting power ; on the other hand, in 

 the case of some other species of bacteria Miller has 

 made positive statements. 



3. A ferment which dissolves cellulose is produced 

 presumably by the bacillus butyricus and by vibrio* 

 rugula, probably also by various other bacteria. Accu- 

 rate investigations on this matter are wanting. 



4. Peptonising ferments, which convert albuminous 

 materials into soluble diffusible forms. In addition to 



* Bourquelot, Compt. rend,, vol. 97. 



t Kjeldahl, Meddedelser fra Carlsberg Labor., vol.i., Parts 2 and 3, 



fioux, Bull. soc. chim., vol. xxxv. 



Cellulose 

 ferment. 



Peptonising 

 ferments. 



