342 UTILITARIAN ZOOLOGY 



large Centipedes (Scolopendra) which abound in tropical countries 

 are well known on account of their painful and poisonous bites. 



PERSONAL ENEMIES AMONG ANNELIDS (ANNELIDA). Some of 

 the Leeches, especially the Land- Leeches of tropical countries, are 

 peculiarly unpleasant to encounter (see vol. ii, p. 148). 



PERSONAL ENEMIES AMONG FLAT-WORMS (PLATYHELMIA). 

 Among the Flukes (Trematoda) about eleven different species 

 have been described as parasitic in human beings, including the 

 kind which causes " liver-rot" in sheep, and which will be the 

 subject of further notice. On one notorious scourge of the sort 

 (Bilharzia hczmatobia) Gamble remarks as follows (in The Cam- 

 bridge Natural History) : " This formidable parasite was dis- 

 covered by Bilharz in 1853 in the veins of the bladder of patients 

 at the Cairo Hospital, and is remarkable from its abundance on 

 the east coast and inland countries of Africa from Egypt to the 

 Cape, as well as in the districts bordering Lake Nyassa and the 

 Zambesi river, while westwards it occurs on the Gold Coast. 

 Mecca is a source of infection whence Mohammedans carry the 

 disease to distant places. In Egypt about 30 per cent of the 

 native population is affected by the serious disease known as 

 haematuria, resulting from the attacks of Bilharzia, so that, of 

 the many scourges from which in Africa man suffers, this one is 

 perhaps the most severe." 



A number of Tape- Worms (Cestoda) infest the human subject, 

 and one example has been given in an earlier volume (vol. i, 

 p. 441), i.e. the Common Tape- Worm (Tcznia soliuin), which is 

 a common consequence of eating " measly " pork in a partially 

 cooked condition. Another not infrequent human parasite in 

 Western Europe is the Beef Tape- Worm (Ttznia saginata\ derived 

 from " measly " beef. The Broad Tape- Worm (Bothriocephalus 

 latus), which is well known as a parasite of man in Russia, Switzer- 

 land, North America, and Japan, results from eating diseased fish, 

 especially pike, which have not been sufficiently cooked. All these 

 three forms attain their adult state in the human intestine, from 

 which they can be expelled with comparative ease by suitable 

 drugs. Another tape -worm (Ttznia echinococcus] which when 

 adult is found in the dog's intestine, is a much more dangerous 

 parasite to man, in whom it may occur in its earlier bladder- worm 

 form of existence as a swelling or cyst in the lungs or liver 

 {Echinococcus veterinorum, fig. 1 240), often with fatal consequences. 



