L88 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the sediineni is inoculated into tubes of the special medium. Of 32 



specimens examined, '.) weiv positive, 6 contaminated, and 7 were nega- 

 tive. Two of the positive cultures were inoculated into guinea-pigs, 

 both of which contracted tuberculosis. 



Immunization of Rodents against Naturally Pathogenic Para- 

 typhoid Organisms.* — J. Danysz and Z. Skrzynski have attempted 

 to protect mice and rats against infection with Bacillus typhi murium. 

 type B (which is a paratyphoid organism naturally infective for these 

 rodents) with entire lack of success. They employed the following 

 techniques in these attempts — («) vaccination with heated cultures or 

 emulsions (Method of Chantemesse) in one, two or three injections ; 



(b) vaccination with ether-killed cultures (Method of Vincent) ; 



(c) vaccination with cultures killed by dry heat at 75° 0. (Method of 

 Lcemer) ; and (d) vaccination with sensitized cultures killed by dry heat 

 at 75 C. (Modification of Besredka's Method). 



As stated, it was found to be impossible to vaccinate the mouse 

 by any of these methods or to obtain from it a specific serum. From 

 this fact the authors infer that the mouse does not possess any natural 

 defensive mechanism against infection by the organism. The rat, 

 however, is almost as difficult to vaccinate, though much less sensitive 

 to the disease, and consequently one is driven to conclude that this 

 is due to an inherent peculiarity in the nature of the microbe. Guinea- 

 pigs and rabbits, on the other hand, are very easy to vaccinate against 

 B. typhi murium, type B. These animals are refractory to infection 

 per os or by subcutaneous inoculation, but readily succumb to peritoneal 

 infection. The authors therefore conclude that the possibility of 

 immunizing animals naturally resistant to a disease, against an infection 

 artificially provoked, does not permit one to conclude that it is possible 

 to immunize by the same methods animals naturally sensitive to the 

 same disease. 



Adaptation of Lactose Fermenting Organisms to the Medium 

 in which they are grown. f — C. Richet has published a memoir on 

 the above subject in which he demonstrates that an organism that 

 has lived on a medium A grows more easily on the medium A than an 

 organism of the same origin which has grown upon a medium different 

 from A. The organism thus becomes accustomed to the medium A and 

 transmits this peculiarity to its descendants. In estimating the measure 

 of acidity produced by lactose-producing organisms in mixtures contain- 

 ing various quantities of toxic substances the technique employed was as 

 follows : — 



To cow's milk was added an equal quantity of distilled water, followed 

 by a few drops of phthaline ; potassium hydrate being introduced until 

 a suspicion of a pink colouration appears. No more potash than 

 necessary should be added, as during the subsequent sterilization, 

 caramalization of the lactose is apt to occur and thus obscure the end 

 reaction. Ten c.cm. of the solution, accurately measured, is delivered 



* Ann. Inst. Pasteur, xxix. (1915) pp. 55-70. 

 t Ann. Inst. Pasteur, xxix. (1915) pp. 22-54. 



