152 HEALTH AND DISEASE 



SQUAMOUS INFLAMMATIONS 



Pityriasis and psoriasis are the two affections which come properly 

 in this class. 



Pityriasis, as the name implies, is a disease of the skin in which the 

 surface becomes covered with white scales having the appearance of bran. 

 It is usually associated with poverty, and disappears as the general con- 

 dition improves. Horses suffer from the disease occasionally, but not so 

 frequently as cattle. 



Treatment. — According to Williams, the disease in the horse is asso- 

 ciated with presence of oxalates in the urine, and he accordingly advises 

 that carrots and turnips and all kinds of food which furnish sugar should 

 be withheld. AVe would, however, suggest a liberal allowance of green 

 food when such can be obtained, and a generous but well-regulated corn 

 ration. The chief object to be obtained is to improve the nutritive function 

 of the skin. For this purpose a powder consisting of equal parts of sulphur, 

 resin, and nitrate of potash should be given twice daily, and a dose of solu- 

 tion of arsenic with the mid-day feed. The patient should not be allowed 

 to lead a sedentary life, but be freely exercised every day. 



Psoriasis. — The characteristic features of this disease are the accumu- 

 lation of scales in raised patches and thickening of the underlying skin. In 

 the horse psoriasis mostly prevails in the heavier breeds, and especially 

 among animals fed up for exhibition. It is chietly limited to the neck 

 close to the mane, the inner aspects of the ears, and over the tail. The 

 affection commences in circumscribed spots, which gradually extend and 

 unite to form large scaly patches. In the bends of the joints it is gener- 

 ally the case that cracks appear in the skin from which discharge issues, 

 and from the constant movement in the part the fissures do not readily 

 heal, and the irritation which exists sometimes causes general stiffness 

 of the limb and lameness. 



The treatment to be employed is chiefly local. Carbolized oil, or zinc 

 ointment, or in some cases iodine ointment, according to the stage of the 

 disease, may be employed; but it is well recognized that, although the affec- 

 tion may be subdued and kept under for a time, it is extremely difficult to 

 cure. Overfeeding, want of exercise, and dirty stables are common causes 

 of its recurrence when once subdued. 



