SQUAMOUS INFLAMMATIONS 153 



ICHTHYOSIS 



This disease is characterized by more or less hypertrophy of the skin as 

 a whole, but especially by the free and morbid outgrowth and accumulation 

 of epidermis upon it. 



In man it is congenital and hereditary, and it may be so in the horse, 



Fig. 268. Ichthyosis 



but the seldom occurrence of the disease in this animal has not afforded an' 

 opportunity of our forming a definite opinion on this point. 



In the ox it is more common, but inasmuch as it seldom calls for treat- 

 ment its congenital and hereditary nature still remains a matter to be 

 determined. 



Ichthyosis is intimately related to a dry and scaly condition of the 

 skin termed Xeroderma, and between the two affections there does not 

 appear to be any well-marked line of demarcation. When, however, the 

 epithelial collections are considerable, and accumulated into well-defined 

 scales or flakes, the disease is termed Ichthyosis. It would appear, there- 

 fore, that xeroderma and ichthyosis represent degrees of the same disease, 



