si 



220 AMERICAN FARMER'S HORSE BOOK 



In most of these cases, the joint last named is the part really 

 affected. But the mischief very often flows from the same 

 external causes referred to in the last two sections — improper 

 stable management, and permitting the horse to stand habit- 

 ually in wet and filth, or on a mass of rotting straw, saturated 

 with the highly alkaline urine. 



It is an established fact in the pathology of diseases, whether 

 of man or beast, that the same causes acting upon the physical 

 system, under different circumstances, may produce quite 

 different results. Hence arises the fact that many diseases 

 belonging to the same class, yet more or less varied in their 

 developments, and designated by totally different names, are 

 often traceable to precisely the same origin. Why this pecul- 

 iar form of disease in the horse's foot should be called " grease," 

 to the exclusion of others of a very similar appearance, is 

 not apparent from any pathological considerations. The 

 same purulent matter is given forth in thrush and foot-evil 

 as in this. These diseases are evidently most closely related. 

 They manifest the Same, or nearly the same, symptoms ; they 

 often run into each other, and may have exactly the same 

 causes ; and the same treatment cures them. One common 

 title, therefore, might be applied to all of them with perfect 

 propriety ; but, for the sake of distinction and greater clear- 

 ness, they are variously named according to their most promi- 

 inent and distinctive symptoms. The most striking pecu- 

 liarity of this disease, and the only one which marks the 

 Doundary between it and the others, is the cracked, open 

 heel. Throughout this work, therefore, it will be called 

 "cracked heels." It will be of decided advantage for our 

 agricultural and veterinary writers to accept this American 

 name, and drop the vague term of English farriers, " grease." 



In the horse's heel, the skin has one peculiarity not dis- 

 coverable in any other part of the body. In its healthy state 

 there is a constant secretion and discharge of an oily fluid 

 from the cellular tissues underneath. This lubricates the much 

 exposed surface, and keeps it soft and pliable. It also pre- 

 vents the skin from becoming dry and hard, as well as from 



