104 ENTOZOA FOUND IN MAN. 



Chapter XI. 



OXYUmS VEEMICULARIS. 



Synonyms : — Ascaris (Hippocrates and Galen) ; 



Ascaris Vermicularis (Linnaeus). 

 E7i(jl{sh common Name : — Small Thread Worm. 



The oxynrides inhabit the large intestine and espe- 

 cially the rectum, in the lower part^ of which they 

 are commonly found ; they often emerge at the anus. 



They generally exist in considerable numbers, 

 and are sometimes aggregated into a large mass. 

 Although they may be expelled by hundreds, either 

 spontaneously or as the effect of purgatives, they 

 may often be seen, at the end of a week or two, to 

 be apparently as numerous as before. 



Children are much more subject to oxyurides 

 than adults are ; but persons may be affected by them 

 at all ages. 



Nothing definite is known respecting the influ- 

 ence of diet upon the development of these entozoa ; 

 and that of the seasons is equally obscure. Several 

 writers state that they are more common in the 

 spring and autumn than at any other periods of the 

 year ; but these assertions appear to be based more 

 upon the theory referred to in the chapter upon the 

 Lumbrici than upon actual observation. 



They have been met with in all European coun- 

 tries ; according to Bremser and Bilharz they are 

 very common in Syria and in Egypt ; they have also 



