THE TRICOCEPHALUS DISPAR. 103 



developed until some months afterwards in the water 

 which has washed them from the soil ; at a sub- 

 sequent period they are conveyed by the water which 

 is used for drinking purposes into the alimentary- 

 canal, where their shells are dissolved by the intes- 

 tinal secretions, and the embryos are set free. 



The symptoms which are produced by the pre- 

 sence of these worms in the intestines are almost 

 unknown. Pascal, a French hospital physician, says, 

 in a work upon this subject, that they give rise to 

 the following pathological phenomena when they 

 are very numerous : — Small, hard, irregular, and 

 intermittent pulse, flushed face, prominence of the 

 eyeballs, headache, and pinching pain in the abdomen ; 

 these observations have not, however, been verified 

 by any other writer. 



There is no sign which can be considered as 

 decidedly diagnostic of the existence of tricocephali 

 in the intestines, as, owing to their tenacity of 

 adherence to the mucous membrane they are not 

 usually seen in the evacuations, excepting of persons 

 who are afiected with severe diarrhoea or dysentery ; 

 the discovery of the ova would, of course, serve to 

 complete the diagnosis. 



