200 ENTOMOLOGY FOR MEDICAL OFFICERS 



Prophylaxis against rat-fleas during an epidemic or 

 epizoic of plague is part of the question of dealing with rats — 

 a large sanitary question that cannot properly be considered 

 in an entomological treatise. But it is appropriate to 

 suggest that when an epizoic of bubonic plague is known 

 to exist, ointments or oily applications containing some of 

 the numerous substances known to be repellent to fleas 

 {e.g., quinine, quassia, sulphur, petroleum, turpentine, etc.), 

 should be generally used by people who value their health 

 and are not professed fatalists. 



Ants, though in many ways a pest in a house, will help 

 to rid it of fleas by devouring larvae and pupae. 



