NON-SPORING BACILLI 269 



the great accumulation of the plague bacilli in the peri- 

 vascular spaces. On this view, pneumonic plague is a 

 lobar pleuro-pneumonia of haematogenous origin, and 

 should be classed with croupous pneumonia. Dr. Fujinami 

 confirmed these findings. Professor Zabolotny observed 

 that it had not been sufficiently proved how many were of 

 direct pulmonary origin and how many were of haemato- 

 genous origin. 



Rats and Fleas. Professor Kitasato reported that of 

 30,000 rats examined in South Manchuria, 6 per cent were 

 Mus rattus, but none of the 30,000 showed plague infection. 

 In North China, of 3,000 rats examined living by Dr 

 Andrew, all were Mus decumanus ; he had never found 

 Mus rattus. He had noted a seasonal flea prevalence, 

 highest in September, October, and November. The only 

 species noted was Pulex cheopis. Dr. Petrie found both 

 Pulex cheopis and Ceratophyllus unisus among fleas 

 examined at Mukden. Dr. Petrie also examined twelve 

 tarabagans sent direct from Manchuria to Mukden. On 

 these he found thirty-five fleas, twelve being on one 

 alone. (Ticks were also observed on them.) The fleas 

 found were unusually large, and on superficial examination 

 appeared to belong to the genus Histricopsylla (eyeless, 

 truncated head, comb on the inferior border of head, 

 thorax, and part of abdomen, numerous long hairs over 

 the body). 



In an epidemic of plague in Tongshan, in 1908, bubonic 

 cases predominated at the first, but the proportion of 

 septicaemic and pneumonic gradually increased. Of the 

 rats examined, i per cent were found to be affected. 

 Some rats which remained well for days without any sign 

 of glandular enlargement during life, were found post 

 mortem to have Bacillus pestis in the splenic blood, and 

 were evidently immune to infection, at least for the time 

 being. Rats trapped in the mines in the neighbourhood 

 were found to be less readily infected experimentally 

 than those found above ground. The death-rate in the 

 Tongshan epidemic was 800 out of 1000 cases. 



Diagnosis. Sputum is scanty at first, and the bacilli 

 are difficult to find in it. Later, it is almost a pure culture. 

 Professor Zabolotny advised Gram's method for staining 



