398 TORULACE^E. 



maltose is fermented with difficulty, if at all, whilst the same 

 species are able to split up the other sugars named into alcohol 

 and carbon dioxide. In other cases, e.g., Torula colliculosa, the 

 maltose is fermented only by certain cells present in tjie warty 

 excrescences of the giant colonies, whereas the cells growing in 

 the flat portions of the colonies do not exhibit the least sign of 

 fermentation in presence of maltose. Saccharose is fermented 

 with vigour by a large number of species; but others cannot 

 invert it, though able to reproduce at the expense of this sugar, 

 as they do in the case of others they are unable to ferment. 

 Lactose, trehalose, melibiose and melicitose are not^split up into 

 alcohol and carbon dioxide by the majority of species, and in a 

 few cases the same applies to raffinose. Torula Novce Carlsbergice, 

 Gronlund, ferments dextrin. 



On the other hand, a small group of Torulacece, including the 

 species mentioned above, is characterised by the property of 

 fermenting lactose, and consequently possesses high practical 

 importance. So far as research has been pushed this group 

 exhibits the same characteristic as the others, namely, that glucose, 

 galactose and saccharose are fermented readily, maltose only with 

 difficulty. When grown in beer wort, the non-sporulating, so- 

 called Sacch. pinophthorus melodus, isolated by J. J. van Hest from 

 spoilt beer, generates a gas that burns with a blue flame. 



The fermentative power of a given species varies with the 

 kind of sugar employed. Some of them, when grown along with 

 yeast, are able to hinder the fermentation set up by the latter 

 organism, probably in consequence of their transformation pro- 

 ducts. In some species the amount of alcohol produced is con- 

 siderable. On the other hand, as shown by Heinze, the presence 

 of 10 per cent, of alcohol in the nutrient liquid completely hinders 

 the development of Sacch. laciis, Adametz, and Sacch. tyrocola, 

 Beijerinck, even 5 per cent, being sufficient to suppress fermenta- 

 tion and reproduction almost entirely. Heinze and Cohn found 

 the remarkable ratio of about 3 : 2 between alcohol and carbon 

 dioxide with the last two lactose yeasts in meat-broth cultures 

 containing lactose. Esters are also produced during the fermen- 

 tation. 



With regard to the enzymes of the Torulacece, little is known 

 at present. Invertase appears to be excreted by many of them : 

 compare SCHUURMANS-STEKHOVEN (I.) and E. FISCHER (IY.). 

 According to the researches of H. VAN LAER (VII.), inversion 

 appears only in certain nutrient solutions. On the occurrence 

 of lactase, which was questioned by SCHUURMANS-STEKHOVEN (I.) 

 and E. VON FREUDENREICH (XI.), see E. FISCHER (IV.)- HENNE- 

 BERG (V.) established the presence of catalases, that decompose 

 hydrogen peroxide, in living Torula cells. 



Gelatin is liquefied by all the species hitherto examined, but 

 the nature of the active enzyme remains undetermined. The 



