PHYSIOLOGY AND CHEMISTRY. 399 



Lactomyces inflans caseigrana of Bochicchio produces a lab enzyme 

 and a tryptic ferment (compare p. 63, vol. ii.), and a fat-decom- 

 posing enzyme seems to be produced by several species. Nearly 

 all the Torula species examined by myself are able to liberate 

 sulphuretted hydrogen sometimes to a very considerable extent 

 when sulphur is present in the nutrient solution (compare 

 chap. Ixvi.). 



So far as information is available, the production of acid by 

 Torulacece seems to be inferior to the acid consumption, though 

 the amount produced is fairly considerable in some cases, notably 

 by Kayser's pine-apple Torula (which produces acetic acid and 

 small quantities of a higher fatty acid) and by Clausen's Bretta- 

 nomyces. The Torula cultivated by Weigmann from bad butter 

 produces about 3.6 per cent, by weight of butyric acid when 

 grown in milk ; but, in the researches of Heinze and Cohn, Sacch. 

 lactis, Adametz, and Sacch. tyrocola, Beijerinck, seldom produced 

 more than 0.3 per cent, of acid. Acid is also formed by Gronlund's 

 Torula Novce Carlsbergice and van Hest's Sacch. pinophthorus 

 melodus, the amount varying with the kind of sugar. The nature 

 of the acid in these cases is unknown. With the species examined 

 by Will, on the other hand, the acidity of the beer wort varied, 

 both the decrease (with one exception) and the increase being, 

 however, inconsiderable. The development of one species changed 

 the reaction of even strongly acid sauerkraut water to neutral 

 in a month ; and alkalinity ensued with a less acid medium. No 

 regular connection could be detected between the diminution of 

 acidity and the rapid production of a film growth on the surface 

 of the nutrient liquid. Bail's rhubarb fungi consumed citric and 

 tartaric acids. 



The resistance of the Torulacece to high temperatures is fairly 

 strong in a few species, but varies according to the species, the 

 duration of exposure and the composition of the substratum. 

 The age and physiological condition of the cells are also important 

 factors. After being grown for eight days in wort, seven of the 

 species examined by Will survived exposure to a temperature of 

 65 C. for half an hour, whilst the remainder, under the same 

 conditions, were killed by a temperature of 60 C. In most cases 

 the fatal temperature was the same for wort and water tests. 

 Another Torula, reported by F. SCHONFELD (XI.), possessed still 

 greater powers of resistance, succumbing only when heated to 

 68-75 C. in beer for an hour. On the other hand, van Hest's 

 Sacch. pinophthorus melodus would not stand heating for five 

 minutes at 65 C. The resistance of Meissner's mucinous yeasts 

 terminates between 54.5 and 61 C., and all died when warmed 

 at 45 C. for two hours. The fatal temperature in the case of 

 the lactose-fermenting Torula species is 50 or 55 C. It is 

 therefore evident that, under certain circumstances, the capacity 

 for resisting heat may afford useful diagnostic indications. 

 VOL. ii : PT, 2 2 c 



