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. 



Ajilmals Infested. — The horse, the ox and the dog. 



Parts Infested. — 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. 



Treatme7it . — 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, 



