PLAGUE PROCEDURE IN HONGKONG. 45 



(c) Ceratophyllus fasciatus Bosc. This is found on Mus decumanus 

 and it is the common flea attacking the rat in Europe. It, like Cteno- 

 cephalus canis Curtis, has a comb of bristles behind the head and is 

 thus distinguished from P. cheopis Eothsch. 



(d) Pulex irritans Linn, or the human flea. This is small and light 

 colored, being found exclusively in dark and dirty houses. 



Some curious facts have developed in regard to fleas and their relation 

 to plague. It is a fact that oilmen and dealers in oil never suffer from 

 the infection. Not a single oilman was included among the million who 

 died of plague in Egypt in 1897. Lingi of Pavia records that during 

 twenty-seven years while he was attendant at the pesthouse in Smyrna, 

 he found friction with oil more efficacious than any other medicine as 

 a prophylactic against this disease. In this connection Capt. Ziston, 

 I. M. S., states : 



"Can the relative immunity of Calcutta and Madras compared with Bombay 

 and the Punjab be due to the habit of daily anointing the body with oil in the 

 two former presidencies?" 



It is also notorious that in India visits at night to plague-infected 

 houses have frequently been followed by fatal results, while the same 

 dwellings could be entered with impunity during the day. 



We are now waging war in Hongkong against fleas, the object being 

 as far as possible to kill the ova. When the cleansing work is com- 

 pleted by the tenants, the inspector visits every floor, accompanied by 

 the foreman interpreter and some of the coolies, with a bucket of liquid 

 fuel (pesterine) and some mops, and this is applied to the sides and 

 corners of the floors, and the skirtings and around the partitions of the 

 cubicles. In other districts phenol is being used in the same away as a 

 pulicide. 



The tenants also are invited to have their bedding, clothing, etc., 

 disinfected by steam. By these means it is hoped to destroy the fleas, 

 and it will be interesting to see what effect these measures will have on 

 incidence of plague this year in Hongkong. 



During the dry winter season fleas are remarkably scarce, therefore, 

 this investigation will be continued during the hot, damp months. 



RATS ENCOUNTERED IN HONGKONG. 



• (a) Mus rattus Linn., the black or ship rat. The most common 

 color of this animal is a dirty gray. The tail is longer than the head 

 and body together, is generally slender and tapers to a fine point. The 

 ears are moderately large, standing up distinct out of the fur and 

 extending to the eye and even beyond it when laid forward. The animal 

 frequents roofs of houses and even trees. 



(b) Mus decumanus Pallas., the brown rat, also called the Norway 

 or domestic rat. It is a large rat which in European countries has 



