182 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the ripening of Backstein cheese depends chiefly on a pseudo-yeast or 

 bacterial fermentation extending from the surface, which, at any rate at 

 first, is supported by a pepsin digestion permeating the whole mass of 

 cheese. The conversion of the casein in Emmenthal cheese similarly 

 depends on a bacterial fermentation, real and spurious, occurring 

 throughout the whole cheese mass, and this apparently at first is aided 

 by galactase. 



Relation of Rennet-Enzymes to Ripening of Cheddar Cheese.* — 

 S. M. Babcock and H. L. Russell, who have made experiments on Ameri- 

 can Cheddar cheese with rennet, thus summarise their conclusions. Ren- 

 net extract exerts a proteolytic effect on the casein of cheese, due to the 

 presence of peptic enzymes contained in rennet extracts, the action of 

 which is intensified by the development of acid in the curd. The soluble 

 nitrogenous by-products formed in Cheddar cheese by rennet are the 

 albnmoses or higher peptones that are precipitated by the tannin. 



Formation of Enzymes in Alcoholic Ferments. f — A. Klocker, after 

 discussing whether the formation of enzymes in alcoholic ferments may 

 be used for distinguishing species, comes to the conclusion that Dubourg's 

 contention that yeasts which do not contain a certain enzyme may be 

 induced to produce it if cultivated according to his method, is wrong. 

 Hence the inference drawn by Duclaux is equally wrong, for he says 

 that the action of alcoholic ferments on sugar cannot be used in deter- 

 mining the species. The contrary is the case ; for in this action exists 

 the most constant character of the species. 



y. General. 



Aphides and Flowers. J — Prof. L. Macchiati points out that the re- 

 lation between aphides and the plants they infest is not always one 

 detrimental to the latter. Many species, no doubt, are exceedingly 

 destructive ; but others assist the plant in one of two ways : — In some 

 cases they serve the purpose of an extra-nuptial nectary, attracting- ants 

 and other insects away from the flowers which they would otherwise 

 destroy. In others, they serve, when in the winged condition, as a floral 

 nectary ; visiting the flowers themselves, their sweet excrement attracts 

 Hymenoptera and other pollen- carrying insects in the same way as an 

 ordinary nectary. Various examples are cited of both these uses of 

 aj)hides. 



Myrmecophilous Plants. § — Dr. W. Taliew furnishes a list of about 

 twenty Russian myrmecophilous plants, i.e. such as are furnished with 

 extra-nuptial nectaries or other means for the attraction of ants. 



Effect of Annular Decortication on Herbaceous Plants. || — From 

 experiments made chiefly on species of Crucifera3 and Solanaceae, L. 

 Daniel suggests that decortication of a zone of the stem may be made 

 use of in practice for increasing the size of the fruit, and bringing 

 about other changes also in its substance, flavour, &c. 



* Centralbl. Bakt., 2'° Abt., vi. (1900) pn. 817-25 (3 figs.). 



t C.R. Trav. Laborat. Carlsberg. v. (1900) pp. 58-63. 



t Bull. Soc. Bot. Ital., 1900, pp. 284-90. 



5 Bot. Centralbl., lxxxiv. (1900) pp. 222-4. 



| Comptes Rendus, cxxxi. (1900) pp. 1253-5. 



