PARASITOLOGY. 89 
in from three to four weeks. The leeches reach 
their adult state in about five years, and may live to 
be fifteen to twenty years old. 
Animals Intested.—The horse, the ox and the dog. 
Parts Intested.—Mucous membrane of the mouth, 
pharynx, nasal chambers, eyes and lips. 
Symptoms.—When infested by large numbers there 
is observed loss of appetite, emaciation, anemia, 
hemorrhage from the nostrils or mouth, depending 
upon the location of the leeches; pale visible mucous 
membrane; later weakness and possibly death. A 
single leech, when engorged, will hold two drams of 
blood. When thus filled they loosen their hold, fall 
to the ground, and in this condition can fast a whole 
year. The buccal apparatus of the leeches secretes 
a fluid called hirdulin, which in a measure prevents 
coagulation of blood by precipitating the Calcium 
Salts, so that hemorrhage follows after their detach- 
ment from the mucous membrane. Animals become 
infested through drinking water from infested pools 
or streams. 
Treatment.—Leeches may be removed by throwing 
a strong salt solution upon them, which causes them 
to loosen their hold. They may be removed with 
the aid of a dry towel or with forceps. 
NEMATODA. 
The order Nematoda includes worms that are 
round or cylindrical in shape. They are provided 
with a complete digestive apparatus. There are two 
sexes—male and female; the females always larger 
than the males. They infest various parts of the 
body, as the intestinal tract, vascular system, lungs, 
abdominal cavity, etc. They may produce abscess, 
