286 DISKASES OF THE SKIN. 



Age and Season. — At three and four years of age, 

 when they are first stabled, horses are most liable to display 

 this disorder; autumn and winter are the times they 

 mostly exhibit it ; though an inclement spring may tend to 

 its production. At these periods grease is apt to break out 

 among dealers^ horses, just arrived from the country; and 

 during encampments, it once was prevalent among the cavalry. 



Causes. — The proximate cause is inflammation; or, in 

 the incipient stage, that which we call congestion. Cold 

 and wet predispose the parts to inflame. A horse returning 

 with his legs wet, and allowed to stand long in that con- 

 dition ; or the groom washing the heels, and suff*ering them 

 afterwards to dry themselves, is a very common cause of 

 grease. The groom deserves reprimand whose horse be- 

 comes greasy. There are, however, horses, so rank about 

 the legs, that they require every help the groom can aff'ord ' 

 them ; though gross subjects like these, when in working 

 condition, may, by good stable-management, be kept free 

 from the taint. Also, horses who have been standing com- 

 paratively idle or well fed, and consequently got into fat 

 condition, will, on being suddenly put to hard work, be 

 apt to contract grease. The increased motion of the heel 

 may in part cause it ; in cold weather, or upon dirty roads, 

 the number of times it is made wet and dry; and in hot 

 weather, the dripping of the perspiration down the leg into 

 the heel, may likewise contribute to produce it. But, to 

 recur to the cause I first stated, grease may have a local 

 origin : it may arise from cold and wet ; it may follow a 

 blister to the leg; it may, according to Professor Peall, 

 originate even in the ammoniacal exhalations of the stable. 



Contagiousness. — St. Bel thus speaks of the disease : — 

 " Grease is in general a cutaneous affection, sometimes in- 

 flammatory, sometimes infectious ; and I have known it con- 

 tagious." Dr. Stokes mentions a case, however, in the 

 ' Med. Gazette^ for July 24tli, 1810, which he concludes in 

 these words : " The case shows that a disease remarkably 

 simih'.r to vaccinia might be produced in the human subject 

 by the matter of grease. The only points of apparent dif- 



