4G4 



DISEASES OF THE SKIN 



movable knife-shaped stilettos. The thorax is wrinkled and possesses 

 three pairs of scissor-like claws. The posterior portion of the body is 

 large and possesses nine rudimentary legs. The length of the body is 

 about 2 mm. (see Fig. 1()4 ti). 



Description of the Trichodectes. — In this parasite the head is l)roa(l, 

 quarter-shaped, with three manacle feelers and a tooth-shaped mouth. 

 The thorax is contracted, the posterior part of the body has nine distinct 

 members, and the length of the body is from 1 to 2 mm, (see Fig. 

 164 b). 



The former parasites are the most disagreeable, as they suck the 

 blood from the body, live particularly on those parts of the skin where 

 the hair is thick and which are not exposed to the cold, such as the neck, 

 flanks, and around the base of the tail. The trichodectes feed, as a rule, 

 upon the hair and epidermis, and are found particularly on the head and 



Fig. 164a. Fig. 164b. 



Hsematopinus piliferus. Trichodectes latus. 



The accompanying small lines give the natural size of the parasite. 



neck. Both skin parasites produce intense irritation and rubbing, 

 causing inflammatory efflorescences which look very much like squamous 

 eczema, with partial loss of hair and formation of scabs. The diagnosis 

 is usually easy, as we can see the parasites and their eggs by separating 

 the hair. 



Therapeutic Treatment. — This consists of destroying the parasites 

 and their eggs. For that purpose it is often requisite to clip the animals. 

 The safest and least harmful agents are decoctions of tobacco (5 to 10 

 per cent.), solutions of creolin (3 to 6 per cent.), petroleum (crude, or 

 mixed with benzine, lysol or sapo-cresol) , and in small dogs anise-seed 

 oil (1 to 10 per cent, of olive oil). Mercurial ointment may be rubbed in 

 the neck around the collar, but we must not apply more than a piece the 

 size of a bean, as it is apt to cause salivation. Washing with corrosive 

 sublimate solution has been tried, but it must be carefully done, as the 

 same precaution has to be taken as with mercury ointment, the animal 

 not being allowed to lick the body, as it is very apt to produce mercurial 



