PARASITES OF ANIMALS. 128 
sands of eggs, in which the embryos are considerably de- 
veloped before they are laid. The embryos enclosed within 
the eggs are shaped somewhat like tad-poles, the slender tail 
being bent up against the lower side of the body, which faces 
the flattened side of the egg. The body is broad and well 
fills the egg. The full history of the development of the eggs 
is not yet known. It is probable, however, that a portion of 
the eggs imbedded in the mucus membrane of the intestine 
hatch in that situation, remaining thus in the same person. 
But it is also probable that the eggs that are discharged will 
hatch in water, and that persons become infested by swallow- 
ing the embryos with their food and drink. 
Symptoms. 
The most marked symptom of these parasites is an intoler- 
able itching in and about the anal orifice, which is generally 
worst in the evening or during the night, when the worms are 
migrating or changing their localities. Thisis usually accom- 
panied by sensations of heat and inflammation. Not unfre- 
quently, by irritation of the adjacent nerves, they cause 
similar sensations in the genital and urinary organs, which 
sometimes become very distressing. They sometimes even 
migrate into the genital passages of female children, causing 
great irritation and very serious symptoms. By the irritation 
of the sexual organs, in both sexes, various unfortunate sec- 
ondary diseases and bad habits not unfrequently result, 
especially if they occur at the period of early puberty. Other 
symptoms caused by the irritation of the nervous system, are 
restlessness, general nervousness, involuntary twitchings, 
itching of the nose, chorea, convulsions, and sometimes 
epileptiform seizures. 
Remedies. 
The various medicines ordinarily used as anthelmintics, or 
vermifuges, will often bring away large numbers of these 
worms. Of these the etherial extract of male fern is probably 
the best, but santonine and panna have been used with good 
results. Ordinarily they can be treated more easily and 
effectively by means ofzethjedttons*of cold, or nearly cold, 
