ECZEMA. 



507 



we do not believe in admitting prurigo among the dermatoses of 

 our animals. 



In human medicine the word pruritus serves to designate an 

 itching existing outside of any appreciable alteration of the skin. 

 It is only observed on the extending surfaces of the extremities, on 

 the palms of the hands, soles of the feet, genital organs, and in the 

 neighborhood of the anus. It is evidently an affection of nervous 

 origin. In our animals, the existence of a similar morbid state is 

 not at all demonstrated. 



2. Squamous Chronic Eczema. {Pityriasis, Psoriasis, Mange 



of Inanition.) 



Etiolog'y. Squamous eczema is described under the name of 

 pityriasis or psoriasis in certain special works; it has been identified 

 with these same affections of the human species. This connection 

 is not well founded. Observation demonstrates that the various 

 forms of eczematous processes may pass into a squamous state after 

 a period of variable duration. 



Its causes are those of eczema in general. Among the principal 

 we must mention : uncleanliness, neglected hygiene of the skin, and 

 insufficient alimentation (mange of inanition) or food in a damaged 

 condition. Some fungi have also been incriminated, but without 

 any proof being furnished in support of their pathogenic rôle. 



Symptoms. Squamous eczema is marked by the development 

 of small granular or furfuraceous scabs on the surface of the skin, 

 and under which the derma shows chronic alterations, such as 

 thickening, grayish coloration, induration, etc. ; itching is rare. It 

 is most frequently seen upon the head (especially on the orbits), on 

 the inner surface of the auricular shell, the neck and shoulders, the 

 base of the mane, elbows, hips, at the base of the tail, behind the 

 knee and in front of the hock (sallenders and mallenders). It has 

 an essentially chronic course; its duration varies from a few months 

 to several years. It may be cured without any intervention. 



Treatment. The treatment consists in taking care of the skin, 

 in softening the scabs by means of green soap, and tar or creosote 

 preparations (ointment, liniment, or tincture). Tar and creosote 

 seem to transform the obscure and tenacious chronic inflammatory 

 process into acute phlegmasia which ends rapidly in a cure. Chrys- 

 arobin ointment acts in the same way. 



The expressions psoriasis and pityriasis, which are borrowed from 



