EIGHTH ANNUAL REPORT. 141 



and European red deer. The Strongylus Maria is the one princi- 

 pally found, however. It is a very long filiform worm, of the 

 thickness of stout cotton thread, somewhat attenuated at the 

 extremities and of a white color. The male, 3 cm. to 8 cm. long; 

 female, 5 cm. to 10 cm. long. Upon examination of the female 

 under the microscope, the ovarian coils are usually found to be 

 filled with eggs, oval in shape, .01 mm. in length and containing 

 well-formed embryos. When the ovum is laid the well-formed 

 embryo soon escapes. It is not known to undergo further develop- 

 ment in the bronchia, but if expelled and thrown into water or 

 moist earth, the egg or embryo may remain alive for months. 

 (Baillet). 



Leuckart, who experimented quite extensively with this par- 

 ticular nematoid, failed to produce the disease in healthy sheep 

 by feeding them the bronchial mucus rich in ova and embryos. 

 He found that in the second week of their existence in water, or 

 moist earth, they moulted. He even supposed that they moulted 

 a second time and infested an invertebrate host ; but of this there 

 is no actual proof. He also found that if kept in water many died 

 soon after moulting. I have never succeeded in keeping the adult 

 worm or its embryo alive in water at any temperature longer than 

 2 to 4 days. Ercolani found that if the embryos were dried up 

 after moulting, they could be preserved for a year and revivified 

 when again subjected to moisture. While water seems to be es- 

 sential to the preservation and moulting of the embryo, yet a 

 drought following such moulting might preserve it indefinitely 

 by drying it up, and arresting vital changes without destroying 

 its vitality. 



The worm undoubtedly enters the body through the medium 

 of green vegetation, earth or water. Just how it reaches the lungs 

 — whether by the larynx, in connection with deglutition and ru- 

 mination, or by means of the circulatory system — has not yet 

 been certainly determined. 



It is the unanimous opinion of all observers that the conditions 

 favoring the disease are wet seasons, as in the case of worms gen- 

 erally. The abundance of water favors the preservation of the 

 embryo, and also its moulting, which fits it for a new internal 

 habitat. Grazing on marshy pastures, pools and sluggish streams, 

 or inundated lands are especially favorable to the preservation of 

 the worm, and hence its frequency in countries like Holland and 

 Belgium, and in all damp lands that have once become infested. 



Impaired health from previous or coexistent disease, or from 

 lack of stamina due to inbreeding, must be recognized as predis- 

 posing to the disease by lessening the pozver of resistance. 



