106 ORIENTAL PLAGUE chap. 



inoculated (subcutaneously or cutaneously) with virulent 

 plague material. In some cases, however, owing either 

 to the lessened virulence of material, to the smaller 

 dose, or to peculiarity of a given animal, death does not 

 take place within three or four days — the animal survives 

 up to five, six, seven, or more days. In these subacute 

 cases the inflamed inguinal glands show more or less 

 advanced necrosis in their centres, the necrotic material 

 containing abundantly masses of plague bacilli. The 

 spleen is enlarged, so is the liver. There exists an 

 interesting difference with regard to the condition of these 

 two organs in the guinea-pig and in the rat in the sub- 

 acute forms of plague. The difference is this : while the 

 spleen and the liver in the rat do not (with few excep- 

 tions) in general appearance differ from the condition of 

 these organs found in the same animal dead from acute 

 plague, it is otherwise with the guinea - pig. In this 

 animal the two organs, as also the lungs, are pervaded by 

 small whitish necrotic nodules and patches. Only in a 

 small percentage of rats dead of the subacute form of 

 plague are necrotic punctiform nodules in the spleen and 

 liver found. The necrotic nodules in the spleen and liver 

 of guinea-pigs dead of the subacute form of inoculated 

 plague are similar in appearance to those met with in 

 inoculated pseudo-tuberculosis in the guinea-pig (see my 

 Report 1900-1901). But this latter disease is much 

 slower in progress, and its microbe is totally different 

 from B. pestis (see a former page). 



The above necrotic nodules of the spleen involve 

 chiefly the pulp tissue, in which numerous small and 

 large vessels are to be observed filled with masses of B. 

 pestis. The necrotic nodules in the liver involve both the 



