508 



DISEASES OF THE SKIN. 



human dermatology, have been applied in veterinary medicine to 

 cutaneous diseases of an eczematous nature. 



Psoriasis of man is characterized by an inflammatory infiltration 

 of the papillary body with a horny transformation of the epidermis 

 which covers it. At the outset we observe red pimples (P. punc- 

 tata) which are transformed later into squamous nacreated blotches 

 (P. guttata); later these blotches may reach a diameter of a silver 

 dollar (P. nummularis) ; at times they become confluent and cover 

 large surfaces ; they often heal from the centre and then form ring- 

 or garland-shaped pictures, according to their isolated or confluent 

 condition (P. annularis et gyrata). Its preferred locations are the 

 surfaces of extension of the elbow and carpus, the hairy part of the 

 head, forehead, and ears. We have never observed a similar dis- 

 ease in our domestic animals. 



Pityriasis of man is a very rare dermatosis, which by a redness 

 and desquamation sometimes extends over the whole surface of the 

 integument. It determines atrophy, even gangrene of the skin, 

 general emaciation, and finally death. Such a disease does not exist 

 in animals. 



3. Chronic Impetiginous Eczema of the Eegions which 

 ARE Covered by the Mane. {" Mange^^ of Mane and Taily 

 Plica.y 



The different forms of eczema, but especially the vesiculous and 

 pustular condition, are observed on regions covered with coarse 

 hair, and principally on the upper edge of neck and shoulders 

 (mane mange), and upon the tail (tail mange). As a consequence 

 of the inflammatory action and the nutritive disturbances of the 

 skin, certain pathological products necessarily take part in the pro- 

 cess ; at times the mane becomes aggloti Dated, atrophic changes take 

 place in the skin and connective tissue (plica), sometimes the hair 

 falls out in great quantity, producing the so-called rat tail. 



Etiology. The causes of impetiginous eczema located upon the 

 regions covered by the mane and tail are purely local. We must 

 incriminate, first, uncleanliness and neglected hygiene of the skin, 

 which permit of the accumulation upon its surface of hay-dust and 

 a large variety of irritating bodies. Abundant and felted horse- 



1 The denomination plica has been adopted in Germany, undoubtedly on account 

 of the similarity of the affection with plica of the human species. — n, d. t. 



