PRELIMTNAET EEMAEKS. 175 



This law, to use the language of Erasmus Wilson, resolves 

 itself into three forms of expression : — 1st, That disease affect- 

 ing a 'part of a membrane is liable to spread to the whole ; 2nd, 

 that disease of the mucous membrane may spread to the shin, and 

 vice versa ; and Srd, that disease of apart of a membrane may 

 become translated to a distant part of the shin, and vice versa. 



An intimate knowledge of the above law is of the highest 

 importance in the treatment of those diseases which are 

 peculiar to the skin and to the mucous membranes ; especially 

 those of a chronic, specific, and malignant nature, such as 

 G-rease, Canker, Scarlatina, Farcy, Glanders, and a number of 

 others not necessary to enumerate. 



The colour of the hair of horses seems to hold some 

 mysterious relation to their breed. There are very few 

 thorough-bred horses, comparatively speaking, of a black or 

 iron grey colour, while greys, blacks, and browns are the pre- 

 dominating colours of draught horses. 



Grey horses are subject to one disease which I never saw 

 manifested by those of any other colour, viz., the disease 

 known as Melanosis. 



Formerly the opinion was current amongst horsemen and 

 veterinary surgeons that white legged horses are more prone to 

 attacks of Grease than dark legged ones. My experience, 

 however, does not verify this opinion ; on the contrary. I have 

 found Grease to bear a far more intimate relation to the form 

 of the bones of the extremities than to the colour of the hair. 

 Bound boned horses are more prone not only to Grease, but to 

 other maladies of the skin, than are clean-legged and flat-boned 

 horses. 



