224 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Galactase or Milk-ferment.* — Messrs. S. M. Babcock and H. L. 

 Russell give in more detail an account ofygalactase, the specific proteo- 

 lytic ferment of milk, its properties, and its action on the proteids of 

 milk. Though allied tj other proteolytic eDzymes of animal and vegetable 

 origin, it is different therefrom, and it has received its name on account 

 of its inherent relation to milk. It is present in all mammalian milk. 

 Its action shows that the enzyme belongs to the class of which the best 

 representative is trypsin. It acts powerfully in neutral and faintly 

 alkaline solutions, and is less sensitive to acid reaction than trypsin. 

 Its strongest effect is exerted between 37° and 42°. It rapidly decom- 

 poses H 2 0. 2 . In milk it can be easily distinguished from other animal 

 or bacterial proteolytic ferments by the character of its decomposition 

 products, e.g. from trypsin it is distinguished by forming ammonia. 



The close connection between the action of galactase on milk and the 

 normal ripening of Cheddar cheese leads to the conclusion that these two 

 processes are effected by the same agency. 



Self-fermentation of Yeast.f — By the self-fermentation of yeast is 

 to be understood, says Herr C. J. Lintner, the power possessed by yeast 

 of forming alcohol and carbonic acid at the expense of their own body- 

 substance and without any addition of sugar. The material for tliis 

 self-fermentation is no doubt glycogen, which is first converted into 

 grape-sugar and then into alcohol and carbonic acid. The amount of 

 alcohol produced by fresh bottom yeast in 42 hours amounts to 5 ■ 6-7 ■ 7 

 per cent, of the dry yeast mass. The author's experiments and observa- 

 tions chiefly relate to the action of certain salts on self-fermentation. 

 Starting with the idea that invertin must be easily extracted from 

 plasmolysed yeast, and using a large excess of the salts in order to kill 

 the yeast, he found, contrary to his expectation, that while certain salts 

 inhibited self-fermentation others promoted it. The first set of experi- 

 ments was carried out in small tubes, and the results are shown in four 

 tables. Chlorides prevented self-fermentation. According to the nature 

 of the base, sulphates excited or depressed the action ; sodium and zinc 

 sulphates promoted self-fermentation, while other sulphates repressed it. 

 Acid phosphates hastened, and alkaline phosphates retarded the action. 

 Ammonium salts always inhibited, and nitrates appeared to do so. 

 Distilled water at first delayed self-fermentation. Experiments made 

 with Hayduck's apparatus for the purpose of ascertaining the amount 

 of carbonic acid developed in a given time gave confirmatory results. 



Schizomycetic Fermentation.^ — Herr O. Emmtrling communicates 

 some observations on the fermentation of malic acid by Bacillus lactis 

 aerogenes. The fermentation products were carbonic, acetic, and succinic 

 acids. These results lead the author to suggest that previous observa- 

 tions (Fitz, Pasteur) as to the conversion of malic into succinic acid by 

 Blastomycetes are incorrect, and that the changes found were probably 

 due to contamination with fermenting bacteria. 



* Centralbl. Bakt. u. Par., 2" Abt., vi. (1900) pp. 17-21, 45-50, 79-88 (8 figs.). 

 Cf. this Journal, 1898, p. 219. t Op. cit.. v. (1899) pp. 793-800. 



J Per. Deutsch. Chem. Gesell., xxxii. (1899) pp. 1915-S. See Centralbl. Bakt. 

 u. Par., 2 t0 Abt,, vi. (1900) p. 24. Cf. also this Journal, 1899, p. 637. 



