20 STUDIES IN INSECT LIFE, ETC. 



confined to man it is occasionally found on cats 

 and dogs, whilst, conversely, the cat and dog 

 fleas (Ctenocephalus felis and Ct. canis) from 

 time to time attack man. 



The bite of the flea is accompanied by the 

 injection of the secretions of the so-called salivary 

 glands of the insect, and this secretion retards 

 the coagulation of the victim's blood, stimulates 

 the blood-flow, and sets up the irritation we have 

 all or nearly all felt. 



It is only a few years ago that the spread of 

 bubonic-plague was associated first with rats, 

 and then with rat-fleas ; and at once it became 

 of enormous importance to know which of the 

 numerous species of rat-fleas would attack 

 human beings. The Hon. Charles Rothschild, 

 who has accumulated a most splendid collection 

 of preserved fleas in the museum at Tring, had 

 some years ago differentiated from an undiffe- 

 rentiated assemblage of fleas a species first 

 collected in Egypt, but now known to be the 

 commonest rat-flea in all tropical and sub- 

 tropical countries. This species, Xenopsylla 

 cheopis and to a lesser extent Ceratophyllus 

 fasciatus unfortunately infests and bites man. 

 If they should have fed upon a plague-infected 



