292 DISEASES OF THE SKIN 



which they pass into the vertebral canal, eventually emigrat- 

 ing to the subcutaneous tissue of the back. In the subcutus 

 they become encapsuled in a sac of connective tissue, forming 

 pigeon-egg-sized enlargements which are called warbles. 

 When fully developed the following spring they perforate the 

 skin, pass out through the openings, drop to the ground, into 

 which they burrow and pupate, finally emerging as adult 

 flies. As many as 50 to 100 of these larvae may perforate 

 the skin, causing the hide, which is called "grubby," to be 

 docked one-third in value on the market. Occasionally they 

 may produce emaciation. 



Treatment. — The treatment consists in applying turpentine 

 to the opening over the warble. Those not killed by this 

 method may be pressed out by hand and destroyed. 



Prevention. — ^Applying various disinfectants to the backs of 

 cattle is of no value from a prophylactic standpoint. 



LICE. 



Definition. — ^Lice are blood-sucking parasites (hsematop- 

 inus). Each one of the domesticated animals harbors its 

 own species. They are frequently found on cattle (Hsema- 

 topinus eurysternus), and horses (Hsematopinus equi) . How- 

 ever, occasionally lice will pass from one host to another of a 

 different species. Chicken lice, for instance, will attack 

 horses and human beings. Lice are very prolific. It is said 

 that a single pair may produce in three months 125,000 

 individuals. Lice produce itching, loss of hair, and give the 

 animal an unthrifty appearance. While they may be found 

 on any part of the body they first appear about the neck. 

 As they are large enough to be seen by the naked eye, if the 

 light is good, the diagnosis is usually easy. Even the eggs or 

 nits are visible as small, ovoid bodies attached to the hairs. 



Treatment. — Several remedies will kill lice. For horses one 

 of the most valuable is gray mercurial ointment. Creolin 

 (2 per cent.) is also good. An infusion of tobacco made by 

 boiling tobacco (Biij) in water (Oij) is recommended. A 

 great favorite is kerosene emulsion made by dissolving soft 

 soap (Oij) in boiling water (Oij) and adding kerosene (Oj). 

 This mixture should be churned or stirred violently and 3 



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