v PLAGUE IN THE EAT 113 



tion all but two were found quite normal in every 

 respect. All had perfectly normal viscera ; but one rat 

 had a small gland in the groin at the side on which the 

 inoculation ;(cutaneous at root of tail) had been per- 

 formed, and a second rat had a swollen gland in the groin, 

 about the size of a filbert, also on the inoculated side. 



An incision into the swollen gland, especially in the 

 case of the second rat, showed the interior necrotic ; 

 film specimens made of the gland in both cases showed 

 numerous particles representing bacilli in various stages 

 of degeneration, from rods more or less granular to 

 spherical small and large globules. Cultures on gelatine 

 were made in both cases with relatively large amounts of 

 the gland tissue, and in each instance a fair number of 

 colonies of B. pestis was obtained. The number of B. 

 pestis colonies was, however, incomparably smaller than 

 that induced by a similar proceeding in an unprotected 

 animal when a much smaller particle of a typical plague 

 bubo is used. The colonies (on gelatine) did not on 

 inspection with a glass present any noticeable difference 

 from those of the typical B. pestis that had been 

 initially employed (L.P. I.), except that during the first 

 few days after their appearance they might be considered 

 somewhat less granular and more translucent than 

 usual. In film specimens examined under the micro- 

 scope the bacilli appeared markedly short, certainly 

 shorter than in a similar preparation of the typical 

 L.P. I. The most striking characteristic of this culture 

 and subsequent subcultures was, however, the fact that 

 their virulence was decidedly of a lower degree than that 

 of the B. pestis (L.P. I.) with which the series had been 

 started. 



