THE ANIMAL PAEASITES OF CATTLE. 541 



standpoint. About all that can be done is to feed affected animals 

 well and protect them from exposure. 



PARASITES OF THE BLOOD. 



A spet-ies of fluke {Schistosoma hovis) which lives in the blood ves- 

 sels (the large veins) of cattle in tropical and subtropical countries 

 causes bloody urine, and a condition of the rectum somewhat resem- 

 bling piles. 



The embryos of Filaria labiato-papillosa (p. 540) which occur in 

 the blood may be found by microscopical examination. They appar- 

 ently cause no trouble. 



The organism which causes Texas fever is a protozoan parasite 

 {Piroplasrna higeminum) 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 480 of this volume, or for 

 more complete information con- 

 sult Farmers' Bulletins 258 and 

 378, which can be obtained free 

 on application to the Secretary of 

 Agriculture, Washington, D. C. fig. so.-Lung worm (DMuocauins vivi- 



Other parasites which live in pams) of cattle. 



the blood cause serious diseases 



known as surra and nagana (p. 515), but as yet neither of these 

 diseases has gained a foothold in the United States. 



PARASITES or THE EYE. 



Small roundworms, one-third to four-fiftlis of an inch in length, 

 may occur in the ducts of the lacrimal glands. Several species all 

 belonging to the same genus (Thelaeia) are known. These worms 

 are inaccurately referred to b}' various writers as Filaria lacrimalis. 

 They sometimes escape from their usual location and may be found 

 on the surface of the eyeball beneath the lids, or even in the ej'eball. 

 It has been supposed by some writers that the worms seen in the in- 

 terior of the eyeball ("snakes in the eye") are immature stages of 

 Filaria lahiato-papillosa (see p. 540) which have gone astray from 

 the normal course of their migration, but the correctness of this sup- 

 position 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. 



When worms are present in the eyeball itself, their removal depends 

 upon surgical treatment, usually not advisable, as the worms in that 

 location either cause but little trouble or disappear without treat- 

 ment. 



