ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 501 



of ordinary vaccines. The organism used in his experiments was the 

 Bacillus pseudo-tuberculosis rodentium Pfeiffer, and the research animal 

 was the rabbit. The following were found to be the effects upon the 

 rabbit of the killed vaccine sensitized by Besredka's method, as compared 

 with those of non-sensitized : 



1. The sensitized vaccine has one slight advantage, in that the 

 increase of temperature in injected animals is a little lower on the 

 average than that produced by the non-sensitized, not only after the first 

 injection, but also after succeeding injections. 



2. The animals can generally bear the various series of injections 

 of the sensitized vaccine with much less loss ;of weight than when the 

 non-sensitized is used, so that the former appears to be less toxic, although 

 the number of animals which died of injection is not sufficient to decide 

 this point. 



3. As to the degree of immunity obtained by the injection of each 

 kind of vaccine, there is no appreciable difference, for they both give 

 about the same degree of resistance against various lethal doses when 

 the animals are compared ten days after the last injection of vaccine. 



The production of antibodies in the serum, testable by agglutination 

 and complement fixation, is much less with the sensitized than with 

 non-sensitized vaccine under the same conditions. Thus the estimation 

 of these antibodies in vitro does not show the actual degree of immunity 

 given by the former, as compared with the latter. 



Advantage of using a Broth containing Trypsin in making 

 Blood Cultures.* — S. R. Douglas and L. Colebrook's experiments have 

 confirmed the findings of Wright and his fellow-workers, which showed 

 that when by mixture with trypsin the antitryptic power of blood is 

 neutralized, the blood loses its power of clotting and also its antibacterial 

 properties. These are precisely the changes which it is desirable to bring 

 about when attempting to cultivate pathogenic micro-organisms from the 

 circulating blood. A series of blood cultures performed in duplicate with 

 trypsin broth and simple broth has shown that the employment of 

 trypsin in that procedure is clearly advantageous, the organisms having 

 been in some cases recovered only in the trypsin tubes, while in the other 

 cases they were recovered earlier and more frequently in these than in 

 the control tubes. It is probable that this method favours the cultiva- 

 tion of any microbe that may be present in the blood, and not especially 

 one particular organism or group of organisms, as in the case of bile 

 media. Staphylococci, streptococci, paratyphoid bacilli, anthrax, were 

 readily isolated from blood by the use of trypsin broth. In order to be 

 sure of neutralizing the antitryptic power of the inoculated blood, it is 

 recommended to employ broth containing not less than 5 p.c. of trypsin 

 solution (compound solution of trypsin Allen and Hanbury), and to add 

 not more than 1 c.cm. of blood to each 5-c.cm. tube of such a broth. 

 When a supply of broth is not at hand, or the blood has to be sent by 

 post to a laboratory, undiluted trypsin solution may conveniently be 

 mixed with the blood specimen, immediately on its withdrawal from the 



* Lancet, July 29, 1916, pp. 180-3. 

 Oct. ISth, 1916 2 M 



