392 TORULACECE. 



of highly refractive granules appear. The number of these, how- 

 ever, is usually limited, the highly refractive inclusions forming, 

 a very characteristic element of the cell contents. This applies 

 particularly to the typical Torulacece, the species of the first 

 sub-group. 



As a rule, the globular cells contain an oily particle which 

 seems to have been regarded by some authors as a nucleus. It is 

 barely visible in submerged growing cells with homogeneous 

 contents, and comes into prominence only on the appearance and 

 growth of vacuoles, especially when the cells in film vegetations 

 come into contact with the air. Even when the vacuoles have 

 attained considerable dimensions, and the plasma has diminished 

 to a mere stratum lining the cell wall, the oil particle remains 

 coated with a layer of plasma. Usually globular, it is not 

 infrequently flattened in appearance. The presence of an oil 

 particle in the lactose yeasts characterises them as belonging to 

 the Torula group. RAUM (III.) differentiated one of these in 

 kephir yeast by staining and assumed it to be a Torula form in 

 the sense defined by Hansen. The size of the particle increases 

 with the age of the cell and by contact of the latter with air, 

 although, so far as observation goes, it remains small in some 

 species, so that the size of the oil particle may serve as a means 

 for the characterisation of species. The globular and oval cells 

 of some species contain two or more oil particles ; and these have 

 probably been confounded with spores in many instances. The 

 elongated cells of the second sub-group of Torulacece also contain 

 oil particles, distributed in the same manner as those in the cells 

 of Mycoderma. Nevertheless they may also be lacking in species 

 with mixed cells, in the rounded and oval cells of which they occur 

 regularly. 



Crystalline bodies in the vacuoles (see p. 153, vol. ii.) form a 

 highly characteristic inclusion in Torula cells. Of regular occur- 

 rence in a few species, they appear to be lacking in others with 

 morphologically similar cells. Accordingly, they might serve as 

 a diagnostic feature, in the same way as the varying number of 

 oil particles in the globular cells. 



Very old cells of typical Torulacece frequently contain, like 

 those of the Saccharomycetes, a single large globule that is partly 

 of a fatty nature. According to LINDNER (XXXYI. b) small 

 fatty drops are of frequent occurrence in the small cell species of 

 Torula, even under normal conditions, the cells being mostly 

 highly refractive, with a greenish tinge. Torula pulcherrima 

 develops large, highly refractive globules. 



Glycogen was absent from very few of the species examined 

 by the writer, when grown in beer wort or in neutral yeast- water 

 with 6 per cent, of saccharose. The production of glycogen was 

 also observed by Meissner in certain of his mucinous yeasts. The 

 intensity of the reaction varies considerably, but is generally 



