VIII 



AGGLUTINATION OF B. PESTIS 



221 



This rabbit was found dead on July 20. On post-mortem 

 examination the spleen was seen to be permeated by small 

 grey nodules, which on microscopic and cultural examination 

 proved to be of the nature of pseudo-tubercle. No plague 

 bacilli were demonstrable either in the blood or the organs. 



The blood of the rabbit was, however, tested for its 

 agglutination (dilution 1 : 20) on various occasions, with 

 the following interesting results : — 



From this it appears that after the first intravenous in- 

 jection of sterile culture no agglutinin had yet been formed, 

 but that after the second such injection there was, eight 



