THE TRICOCEPHALUS DISPAR. 101 



Chapter X. 



TEICOCEPHALUS DISPAR. 



Synonym : — Trichuris. 



The tricoceplialus has not been known for more than 

 a century. It was first specially described during the 

 epidemic of mucous fever, in 1760-61, of which 

 Roederer and Wagler have left an account ; it is 

 probable, however, that this entozoon had previously 

 attracted the attention of Morgagni. Eoederer and 

 Wagler, supposing that the smaller end of this worm 

 was the tail, gave to it the name of trichuris (from 

 the Greek dpL^, genitive rpixos, a hair, and ovpa, the 

 tail) ; but Goeze, who subsequently found that the 

 small end was really the head, substituted for the 

 original name that by which it is now generally 

 known, tricocephalus (from ^p'f, and Ke(f>a\rf, the 

 head) ; the term " dispar " has been apphed on 

 account of the great dissimilarity between the size 

 of the male and female of the species which occurs 

 in man. 



The tricocephalus dispar exists most commonly 

 in the caecum, and less frequently in the colon ; it is 

 also sometimes found in the small intestines, but it 

 has never been seen in the stomach. 



A tricocephalus which was discovered in the 

 tonsil of a man in the military hospital at Chatham 

 has been referred to the tricocephalus affinis, a species 

 which lives in the csecum of the sheep and other 

 ruminating animals ; but this was, perhaps, a trico- 

 cephalus dispar, which had been expelled from the 



