PHYSIOLOGY AND CHEMISTRY. 397 



Torula Duclaux, and the lactose-fermentating species isolated by 

 E. Kayser from milk, will not adapt themselves to temperatures 

 of about zero C. In the species examined by Will, the optimum 

 temperature varied between 20 and 25 C. ; whereas it lay 

 between 25 and 30 C. for the Hartman's Torula colliculosa, 

 jSacch. lactis, Adametz, and Duclaux's Torula and the lactose- 

 fermenting species of Kayser. In the case of Sacch. lactis, 

 Adametz, the optimum fermentation temperature was 37.5- 

 40 C., whilst Sacch. tyrocola preferred lower temperatures, viz., 

 2 3~ 2 7 G. The optimum temperatures for development and fer- 

 mentation do not always coincide. With Torula colliculosa the limit 

 of growth was reached at 45 C., whereas Hansen found it to be 

 3^~37 G. for several of his Torula species, and in one case 

 3839 C. formed the limit for several of the species examined by 

 myself. Lactomyces inflans caseigrana, Bochicchio, grows very 

 rapidly at 40 C. ; but growth recedes at 45 0. and the fungus dies 

 in a short time at 50 60 C. The optimum growth temperature 

 of Torula amara, Harrison, is 37 C., the limit being 48-5o C. 

 As in the case of the Saccharomycetes, a considerable divergence in 

 the limits of budding temperature is observed among the Torulacece, 

 a circumstance capable of affording valuable diagnostic indications. 

 Growth and reproduction are largely influenced by the 

 admission of air. All the known Torulacece require free oxygen, 

 a characteristic which certainly stands in causative connection 

 with the predominating tendency of many species to grow on the 

 surface of the liquid. This requirement, however, does not 

 extend so far as to necessitate direct contact with the air, growth 

 proceeding also in fairly high strata of liquid. 



Numerous reports are available on the behaviour of the 

 Torulacece towards the various kinds of sugar, e.g., by E. C. 

 HANSEN (XLVL), L. VAN DEN HULLE and H. VAN LAER (II.), 

 E. KAYSER (V.), 6. GRONLUND (II.), V. PEGLION (II.), R. MEISSNER 

 (II.), A. KALANTHAR (I.), 0. BAIL (I.), M. HARTMANN (II.), 

 L. A. ROGERS (I.), J. J. VAN HEST ([.), N. HJ, CLAUSSEN (I.), and 

 chiefly by P. LINDNER (XXXV.). The writer himself has also 

 carried out numerous fermentation experiments with the Torula 

 species he examined. The methods adopted by the various authors 

 differed among themselves. P. Lindner, M. Hart maun and the 

 writer employed the small-scale method (introduced by the first- 

 named) in hollow-ground slides, with yeast water as the nutrient 

 liquid. In any event the nutrient solution used plays a certain 

 part in the fermentation. 



Fermentative power is lacking in only a very few of the known 

 species, such as the majority of Meissner's mucinous yeast, and a 

 few of the Torula forms examined by P. Lindner and the writer ; 

 but, apart from a few lactose-fermenting species, the Torulacece 

 are not extensive alcohol-formers. Most of them ferment glucose, 

 mannose, galactose and fructose with comparative readiness ; 



