for lung worms, including fumigating with different substances and injections of remedies into the trachea by means of a large hypodermic syringe or by a special spraying apparatus, but none have been very successful from a practical standpoint. About all that can be done is to feed affected animals well and protect them from exposure, removing them from the pasture and keeping them in dry yards or stables maintained in a cleanly, sanitary condition.
The methods of prevention in general are similar to those described under the discussion of the twisted stomach worm ([p. 521]).
PARASITES OF THE BLOOD.
Certain flukes (Schistosoma bovis and related species) which live in the blood vessels (the large veins) of cattle in tropical and sub-tropical countries cause bloody urine and diarrhea, the feces being mixed with blood. These parasites have not yet been discovered in the United States, although the natural conditions are such in some parts of the country that they are liable to become established if introduced.
The embryos of Setaria labiato-papillosa ([p. 529]) which occur in the blood may be found by microscopical examination. They apparently cause no trouble.
The organism which causes Texas fever is a protozoan parasite (Piroplasma bigeminum) of microscopic size, which lives in the blood and attacks the red blood corpuscles. For a discussion of this parasite and the disease which it produces see [page 476] of this volume.
Other parasites which live in the blood cause serious diseases known as surra and nagana ([p. 500]), but as yet neither of these diseases has gained a foothold in the United States.
PARASITES OF THE EYE.
Small roundworms, one-third to four-fifths of an inch in length, may occur in the ducts of the lacrimal glands. Several species all belonging to the same genus (Thelazia) are known. They sometimes escape from their usual location and may be found on the surface of the eyeball beneath the lids, or even in the eyeball. It has been supposed by some writers that the worms seen in the interior of the eyeball ("snakes in the eye") are immature stages of Setaria labiato-papillosa (see [p. 529]) which have gone astray from the normal course of their migration, but the correctness of this supposition is uncertain.
Worms in the eyes and lacrimal ducts may cause inflammation, in which case the eyes may be syringed with an antiseptic, such as a weak solution of coal-tar stock dip, and iodoform ointment applied if the condition is severe.