CHAPTER XLIL 



DISEASES OF THE SKIN — Contiuucd. 



fiQUAMOUS INFLAMMATION OF THE SKIN — PSORIASIS — PITYRIASIS — 

 DISORDERED SENSIBILITY OF THE DERMA — PRURIGO — INFLAMMA- 

 TION OF THE SEBACEOUS FOLLICLES ACNE — SITFASTS — TREAT- 

 MENT. 



SQUAMOUS INFLAMMATION OF THE SKIN, 



Diseases characterised by inflammation and hypertrophy of the 

 derma, and the production on the diseased skin of laminae or 

 scales. Of this disease we have two examples, namely, psoriasis 

 or dry tetter, and pityriasis. 



PSORIASIS, 



"A chronic and non-contagious inflammation of the derma, 

 characterised by the development of patches, which are irregular 

 in form and size, and covered by irregular scales of epithelium. 

 The patches are raised above the level of the surrounding skin ; 

 they are flat upon the surface, or somewhat more elevated in the 

 centre than at the circumference, and are frequently intersected 

 by deep fissures and chaps, particularly where the disease occupies 

 a surface of large extent." — (Wilson.) 



In the horse we have familiar examples of the above in what 

 have been already mentioned, namely, psoriasis carpi et tarsi, or 

 maUenders and sallenders. At first mallenders and sallenders 

 are generally due to an eczematous eruption, but as they become 

 chronic, the discharge with which they are attended in the earlier 

 stages ceases to flow, and the disease is characterised by the 

 formation of scales. 



Psoriasis is usually met with in horses otherwise quite 



