88 SUMMARY OF CURRENT RESEARCHES RELATING TO 



regards their biochemical actions on certain organic compounds, which 

 serve to differentiate and identify the varieties of these organisms. He 

 has selected nine tests for this purpose, viz. litmus milk, neutral red 

 broth, and broths containing respectively saccharose, lactose, raffinose, 

 inulin, salicin, coniferin, and mannite, and as additional tests in special 

 cases he uses broths containing rhamnose, glycerin, and sorbite ; the 

 reactions of the various streptococci to these tests are given in tabular 

 form. The author has applied similar methods of observation to 

 staphylococci obtained from different sources. Although this group of 

 cocci admits of subdivision into three main types according as the colour 

 of the colonies is white or grey, yellow, and orange or golden, the author 

 finds that the varieties found in these types may be differentiated and 

 identified by their biochemical reactions, and he has established nine 

 tests for this purpose, viz. liquefaction of gelatin, clotting of milk, 

 peptonising of milk, reduction of nitrates to nitrites, changing of colour 

 of neutral red broth, production of acid in litmus broths containing 

 respectively lactose, maltose, glycerin, and mannite. 



Bacillus of the Olive Tubercle.* — E. F. Smith, referring to a paper 

 by Schiff, in which it is stated that the bacillus of the Olive Tubercle 

 coagulates milk and readily forms spores which are very resistant, 

 surviving 15 minutes exposure to 120° C, finds, after long continuous 

 observation of three different strains of this organism, that it does not 

 produce spores in broth, none being visible under the Microscope, and 

 cultures are sterilised by exposure for 10 minutes at 50° C. ; he finds 

 also that milk is neither coagulated nor rendered acid, but gradually 

 becomes alkaline. By inoculating healthy plants with cultures of this 

 organism tumours resulted, control inoculations failing. He thinks 

 that no olive tubercles can be produced with pure cultures of the spore- 

 bearing organism of Schiff ; this bacillus has peritrichous flagella, or is 

 non-motile, whereas the true olive knot organism is motile and has 

 several polar flagella. 



Microbes in Cheese-Making.f — P. Maze finds, from the results of 

 his researches, that cheese-making depends entirely on lactic fermenta- 

 tion and the phenomena that accompany it. Lactic acid fermentations 

 eliminate or hinder all the other fermentations liable to be present in 

 the milk ; they facilitate the drying of the cheese, and communicate to 

 the casein the aroma of butter and cheese. When the refining of the 

 cheese commences, the lactic acid ferment dissolves a part of the casein, 

 but the other ferments also act in the process, as shown by the casease 

 they produce, and by the ammonia they set free. The best cheeses con- 

 tain neither lactic acid nor ammonia, since these favour a too complete 

 solution of the casein and the formation of nitrogenous matters and 

 toxic products dangerous to the consumers. He advocates the employ- 

 ment, in cheese-making, of pure cultures of ferments and pasteurised 

 milk. 



Bacillus Producing 1 Red Pigment only on a Single Medium.^ — 

 M. Didlake has isolated from the reservoir water of Lexington, Ken- 



* Ceutralbl. Bakt., 2te Abt., xv. (1905) p. 198. 



t Arm. Inst. Pasteur, xix. (1905) p. 481. 



X Centralbl. Bakt., 2te Abt., xv. (1905) p. 193. 



