LICE 



917 



This is the brown sewer or ship rat, which is supposed to have come from 

 China to Europe, and from Europe to India. It is the plague rat of Bombay. 

 It is very prohfic, producing several litters of eight to ten young per annum. 



The chart of plague is as follows: — 



Plague. 



Organism. 



Infected 

 Host. 



Infected 

 Reser- 

 voir. 



Transmission. 



Propa- 

 gative 

 Host. 



Infection. 



Bacillus 

 pestis. 



Man. 



Murinae. 



Bacilli 

 obtained by 

 biood-sucking. 



Ingestive. 



Fleas. 



Bacilli in faeces 

 into wound b}^ bite. 



Contaminative. 

 More rarely 

 inoculative. 



3. LICE. 



Relapsing Fevers— With the downfall of Schaudinn's views many 

 authorities consider spirochsetes to be bacteria — e.g., Dobell con- 

 siders them to be such because the longitudinal division is said to be 

 based on imperfect observation, and hereditary transmission can 

 occur with Bacillus cuenoti in the germ cells of the cockroach. 



Fig. 477, — Pediculus corporis de Fig. 478. — Pediculus corporis de 

 Geer, 1778: Male. Carrier of Geer, 1778: Female. Carrier 

 Typhus, etc. of Typhus, etc. 



(From a photograph by J. J. Bell.) 



Many of them are said to be flagellate; their nucleus is diffuse, like 

 bacteria, and there is no conjugation, sex formation, or encystment 

 known, and it would appear as though a coccoid-like infective 

 granule was the important method of their infection of the host. 



