604 SUMMARY OF CJUREENX RESEARCHES RELATING TO 



prodiffiosus does not require an acid reaction of the medium ; an acid 

 reaction intensifies the pigment, but kills the organism rapidly. By 

 growing in slightly alkaline medium the intensity of the pigment 

 diminishes gradually until the death of the micrococcus, all shades of 

 colour from bright red to yellow and white being observed. It is 

 possible also to obtain an identical series of diminishing tints by the 

 addition of progressively increasing quantities of alkaline salts. 



Bacillus coli in Oysters.* — A. Gautiehas compared the numbers of 

 B. coli in oysters taken direct from the pools at Cette, and to which 

 cases of typhoid had been traced, with oysters from Marennes taken 

 from tlie market at Toulouse. The bacteriological analyses of the water 

 in the shells and of the bodies of the oysters were made separately. The 

 results showed that B. coli was present in 2Q out of 80 specimens of the 

 oysters from Cette, and only in 5 out of 30 of those from Marennes. 



Capsule of Bacillus anthracis.f — T. Stiennon finds that the en- 

 capsuled anthrax bacilli which appear in an infected subject, or in 

 cultures grown on ascitic fluid, Ijlood-serum, etc., are not phagocytosed 

 and kill more rapidly than the uon-encapsuled bacilli of ordinary 

 cultures. It seems there exists in the blood some product which the 

 bacterium utilises to form its capsule, which shields it from the phago- 

 cytes and assists it in overcoming the resistance of the subject. 



Agglutinability of the "Bacillogfene" of Tetanus. | — G. Rosenthal 

 has investigated the agglutinability of cultures of bacillogene of tetanus 

 in 24-hour old broth. The addition to one drop of the culture of one 

 drop of anti-tetanic serum gave an immediate agglutination ; with a 

 dilution of 1 in 10, agglutination resulted in half an hour ; with a 

 dilution of 1 in 400, in two hours ; and with 1 in 500 only a slow partial 

 agglutination. The positive reaction with 1 in 400 being superior to 

 the agglutination of 1 in 100 obtained with normal serum, indicates the 

 retention of specific properties by the culture. A mixture of one drop 

 of culture and one drop of anti-diphtheritic serum gives incomplete 

 agglutination after a quarter of an hour ; in a 1 in 10 dilution no sign 

 of agglutination occurred after an hour and a quarter. 



Homogeneous Cultures of Bacillus mesentericus.§ — Lafforgue has 

 grown B. mesentericus in broth so that the characteristic pellicle was not 

 formed and the culture presented a homogeneous appearance. This was 

 attained by two methods. (1) Subcultures were made from the clear 

 broth drawn oif from beneath a pellicle at definite intervals of time- 

 care being taken that the pellicle remained intact. The earlier speci, 

 mens still formed pellicles, though more slowly, but those taken after 96 

 and 120 hours gave no pellicfe and formed perfectly homogeneous 

 cultures. (2) A 5-day old broth culture is sterilised and filtered, the 

 filtrate is inoculated with a fresh B. mesentericus, and a uniformly 

 clouded homogeneous culture results. 



The author finds that the filtrate, as compared with the initial broth,. 



* C.R. Soc. Biol. Paris, Ixii. (1907) p. 766. t Tom. cit., p. 821. 



X Tom. cit., p. 7Si. S Brit. Med. Jom-n., 1907, i. pp. 884, 1177, 1195. 



