152 



Scientific Proceedings (ioo). 



At P H + 7.0, the minimum generation time at 36.0 0 C. — 

 37.0 0 C, is 31 minutes. Maximum growth begins on the average 

 after five hours incubation. 



At P H + 7.8, the minimum generation time is 33.4 minutes. 

 The maximum rate of growth is reached by the eighth or ninth 

 hour. 



At P H + 54 the minimum generation time is 41.3 minutes. 

 The maximum rate of growth is reached after 9f hours. 



85 (1460) 



The pathogenicity of bacterium melitensis for guinea pigs. 



By K. F. Meyer, E. C. Fleischner and E. B. Shaw. 



[From the George Williams Hooper Foundation for Medical Research, 

 University of California Medical School, San Francisco.] 



The very close relationship of B. abortus (Bang) to B. meli- 

 tensis demonstrated by A. C. Evans 1 has been confirmed by our 

 observations. Experimental studies, to be published in the near 

 future, have furnished two additional characteristics of similarity. 



1. The guinea pigs infected with B. abortus developed striking 

 reactions of cutaneous hypersensitiveness with melitensis-protein, 

 and vice versa in animals successfully infected with B. melitensis 

 skin reactions are obtained with aborto-protein (see Table I.). 



2. In a series of attempts to infect guinea pigs with various 

 known strains of B. melitensis obtained from the Hygienic Labor- 

 atory, U. S. Public Health Service (same strains as studied by 

 Miss Evans), we finally succeeded in producing by intratesticular 

 injection of 1/10 agar slant (48 hours' growth on peptic digest 

 agar) a disease with pathological changes which could not be 

 distinguished from those seen in about one hundred guinea pigs 

 suffering from abortion disease. The lesions of two guinea pigs, 

 which consisted of a very large spleen, general lymphadenopathy, 

 liver and lung lesions with infiltrations of epithelioid cells and 

 lymphocytes were only definitely diagnosed to be the result of a 

 B. melitensis infection by cross agglutination and absorption 



1 A. C. Evans, J. Infec. Diseases, 1918. xxii., 580. 



