394 TORULACE.^. 



general characteristic of the giant colonies of this first sub-group, 

 and are not confined to the Torula form isolated by M. HART- 

 MANN (I.) from a dried yeast purchased in Java. Consequently, 

 the specific name, colliculosa, applied to this Torula does not by 

 any means characterise this species. Moreover the fact stated 

 by Hartmann, that these excrescences are composed of large 

 cells, is not confined merely to this species. 



In many forms the surface of the giant colonies bristles with 

 numerous tufts. The nature of the nutrient medium has no 

 great influence on the form of the giant colonies, the character 

 and colour of which, moreover, are highly diversified. In many 

 cases the colour is characteristic of the species : pale pink, yellow 

 or yellow-brown, both in the film vegetations and in the giant 

 colonies ; though sometimes it is confined to, or attains its greatest 

 intensity in, the latter, which thereby acquire increased diagnostic 

 importance. Mostly, the colonies are colourless. They may be 

 mucinous, gelatinous, or more or less dry, dull, semi-matt, or 

 shining like cut glass or mother-of-pearl. Some species produce 

 giant colonies of a waxy character or resembling enamel. 



300. Physiology and Chemistry of the Torulaceae. 



Reproduction in liquid nutrient media, like that on solid sub- 

 strata, depends on the composition, reaction and concentration, 

 as also on temperature and other external conditions, but 

 primarily on the species itself. In a large number of species 

 compared by the writer, the most favourable development took 

 place in neutral yeast water containing 6 per cent, of saccharose, 

 next in order coming the cultures in hopped and unhopped beer 

 wort, and those in saccharine yeast water with an addition of 

 0.5 per cent, of peptone. Even a small quantity of peptone has 

 great influence on the development, though asparagin also forms 

 a good source of nitrogen. According to BETJERINCK (XIX. and 

 XXV.) and J. SCHUURMAKS-STEKHOVEN (I.), Sacch. Kefyr also 

 assimilates succinic acid ; and growth is likewise stimulated by 

 ethyl alcohol. Hayduck's nutrient solution is the least suitable 

 food-stuff for the Torulacece. The Torula species examined by the 

 writer also grew well in beer, provided the liquid was not too 

 deep. Meissner's mucinous yeasts throve in Raulin's solution, 

 but less favourable results were obtained with E. Laurent's 

 nutrient solution. All the writer's Torula species developed in 

 milk, and in some cases produced a cheesy smell, whilst in isolated 

 instances the milk was coagulated. Among the lactose yeasts 

 which also thrive in this medium, Laclomyces inflans caseigrana 

 alone produces coagulation without any important formation of 

 acid. The coagulum is partly reliquefied. Certain of the muci- 

 nous species develop very slowly indeed in all the nutrient media 

 examined, growth proceeding exclusively at the bottom of the 



