194 TROPICAL MEDICINE AND HYGIENE 



their hold. They should not be forcibly pulled off. 

 In a badly infested jungle the clothes, boots, &c., should 

 be damped with a salt solution. This usually serves as 

 a sufficient protection, but may require renewal from 

 time to time. Some persons, where sea water is available, 

 walk through it with their clothes on prior to visiting 

 the jungle; others urinate inside their clothes, a measure 

 that is said to be efficient. 



The best known species of leeches is the jungle 

 leech of Ceylon, the Hcemadipsa ceylonica. In the Malay 

 Peninsula several species are common. 



Many parasites maintain their vitality for a considerable 

 period in the stomach of leeches, but leeches are not 

 known to act as carriers of disease. 



ARTHROPODA. 



Pentastomidce are worm-like animals usually with 

 numerous ring-like constrictions. These are not seg- 

 ments. There is a head which may, or may not, be 

 separated by a neck. The mouth is median, and on each 

 side is a row of hooks. There is a complete intestine 

 ending in a terminal anus. They are bisexual, and the 

 uterus opens externally in front of the anus. The male 

 genital opening is behind the mouth. 



There are no traces of legs in the adult forms, unless 

 the hooks are these representations, but rudimentary 

 legs, four in number, are found in the embryos. It is 

 suggested that they may be degenerate vermiform acarina. 



Two hosts appear to be necessary, The definitive hosts 

 are usually snakes and a large number of species are now 

 known. Birds are the definitive hosts of some species. 

 The adult forms live in the lungs or nasal cavities. The 

 eggs are discharged with nasal mucus and swallowed by 

 a second host mammal, bird, or fish. The larvae are set 

 free and travel into the tissues of the intermediate host, 

 and escape only when the flesh is devoured. On the 

 West Coast of Africa. the Pentastoiuum constrictum, found 

 in the liver in man, is the larval stage of a Porocephalus. 



