FOUR CASES OF PYREXIA 



235 



were employed, and in order that the emulsion of the various bacilli should in each 

 experiment be approximately of the same opalescence, a series of tubes of the same calibre 

 was used and a paper, having parallel lines on it, i)laeed behind tliesc tubes. The strength 

 of the emulsion was gauged when these parallel lines were just visible through the tubes 

 containing the emulsion. A reading of the agglutination was taken after the tubes had 

 been incubated at 37' C. for two hours, and a second reading was taken 24 hours 

 afterwards. These macroscopical findings were also checked microscopically, and the 

 highest agglutinating titre was thus estimated, and was as follows : — 



B. tijphosus rabbit's serum, agglutinated a strain of B. ti/phosmi in a dilution of 1 in 100 

 in 24 hours. 



B. paratyphosus B. rabbit's serum, agglutinated B. parntiiphoid in a dilution of 1 in 400. 



The serum of the rabbit, inoculated with the new organism, agglutinated this organism 

 in 1 in 200 in 24 hours. This serum was then tested against the strains of B. typhoswt and 

 B. paratyphosus B., and the results of this experiment were as follows: — 



Agglutination 

 tests 



In order to employ further differentiation tests between this new organism and the 

 B. typliosus and B. paratypJwId />'., a few absorption tests were carried out. The method 

 employed was that used by Castellani' in order to differentiate organisms further than by 

 their agglutination reactions. 



The principle of the test has been really applied as a diagnostic aid in cases of mixed 

 infections, and, as an aid to differentiating allied groups of organisms, it ought to be a 

 valuable one, for it stands to reason that, if specific agglutinins can be produced in a serum 

 as a result of vaccination with a known organism, and if these agglutinins can be removed 

 by this organism as well as by a heterologous one, when the serum is saturated with them, 

 then these two organisms are probably identical. Bainbridge- has applied this principle 

 in a series of absorption tests carried out with food-poisoning bacilli and found -Absorption 

 it a reliable one. 



' Castellani, A. (1902), Zlsclif. f. Hi/ff., Leipzig, Bd. XL., S. 1. 



- Bainbridge, P. A. (April, 1909), " Paratyphoid and Food-poisoning Bacilli. 

 Ilufffi'lolmfif. 



Jiiiiriuit (if I'athologi/ and 



