GREASE, 771 



A. DISEASES OF THE GLAND-STRUCTURES. 



In the horse, disease of these accessory structures of the 

 skin are almost entirely represented by that condition com- 

 monly recognised by the term ' Grease.' I have placed this 

 affection here, although perfectly well aware that, as usually 

 seen by us, many and different structures are affected ; that from 

 the character of the morbid action and textures involved, it 

 might with as much propriety be ranked with the impetigenous 

 catarrhal inflammations of true cutaneous tissues, as relegated 

 to disturbance and impairment of function of the sebaceous 

 glands. 



Still, it seems that at first and early in its appearance the 

 gland-structures, especially the sebaceous, are the parts most 

 distinctly involved. After some time the changes which the 

 disordered condition exhibits may in a large measure account 

 for the variations in the names by which it is recognised. 



Certainly in the more advanced cases the suppurative action, 

 combined with the extensive involvement of the skin, seem to 

 entitle it not inapproj)riately to be spoken of as Erysipelatous 

 Iiivpetigo — Impetigo ETysipelatoides. 



This affection, of a common inflammatory character attack- 

 ing the gland and cutaneous tissues, must not be confounded 

 with the much rarer state of a specific eruptive, inflammatory 

 action in connection with dermal structures in the same situa- 

 tions, viz., the skin of the heels and posterior parts of the fet- 

 locks of the horse's limbs. 



Pathology, a. History. — From an early period suppurative 

 inflammation of the heels of horses has been noted, and much 

 divergence of opinion expressed regarding it. Of one form at 

 least, probably that which we have spoken of as specific, much 

 has been said as to its specificity and close alliance to variola — 

 as being, in fact, equine variola, and of having, when communi- 

 cated to man, a specific action and influence of a protective 

 nature. This action and influence, if correct as pertaining to a 

 specific eruptive and suppurative disease of the skin of the 

 horse's heels, is certainly not extended to or possessed by any of 

 the products of this common morbid action of which we now 

 speak. Experimentation proves this. 



h. Anatomical Characters. — In the earlier and mildest 



49—2 



