696 PSORIASIS. 



are not pushed too far. When arsenic or its combinations can 

 no longer be tolerated, the tincture of cantharides may be tried ; 

 and lastly, should these prove ineffectual, sulphuric acid may 

 be internally administered. Of all local applications tar oint- 

 ment is the best. 



PITYRIASIS, 



A name derived from the Greek word ir'iTvpa, "bran, and given, 

 to a morbid condition of the skin, characterised by the rapid 

 production of numerous fine white scales, with no exudation into 

 the derma, and no albuminous secretion on tlie surface. 



This is a v^ery common disease among horned cattle, particu- 

 larly young stock, and affects \rai:ious parts of the body, the neck 

 <<ud shoulders, the rump, sides, &c. ft is accompanied by some 

 degi-ee of itchiness, and the scurf often furnishes a habitat for 

 the production and development of vermin. 



The development of pityriasis seems to be due to an ill-fur- 

 nished condition of the animal body, arising from poor food, 

 and it generally prevails in the winter and early spring months, 

 and disappears spontaneously when the cattle are put into good 

 pastures. 



The treatment must consist of good food, the alleviation of 

 the itchiness, and the destruction of the vermin which become 

 associated with it, by sulphur ointment or an ointment of staves- 

 acre. If the disease attack an extensive surface, the sulphur is 

 the safer remedy, as the animals lick their skins, and may take 

 more stavesacre into their stomachs than is good for them. 



Pityriasis in the horse is due to a condition of the system 

 lassociated with the presence of the oxalate of lime in the urine. 



The pathologicil relations of the o^salates, and the conditions 

 conducive to their formation, aie not intended for discussion at 

 present ; but I may point out that the bran-like sc\irf, found 

 on the coats of horses in every way carefully attended to and 

 groomed, is associated with a degree of indigestion, frecj^uent 

 urination, more or less loss of condition, debility, harshness and 

 dryness of the skin, and " hide-bound ;" and that most frequently 

 the disease is found to affect animals which are irregularly 

 worked but otherwise well treated. 



Some kinds of food, such as carrots and turnips, favour the 



