140 GREASE IMPETIGO EEYSIPELATODES. 



Grease may be defined an inflammation of the skin at the 

 back of the fetlock and heels, on which pustules form, yield- 

 ing a fetid purulent discharge ; it is associated with a febrile 

 condition, varying considerably in intensity. 



Symptoms of general disorder usually precede swelling of 

 one or more legs, and especially of the skin of the heel; the 

 hind limbs are more frequently seized than the fore, and the 

 swelling extends upwards over the back of the leg. It is at 

 first like simple phlegmon, with much heat, stiffness, and pain. 

 The exudation sometimes extends up behind the tendons so 

 as to render the knees and hocks rigid. In the course of a 

 few days clusters of pustules rise, which are at first filled 

 with a clear, yellowish lymph. It is this lymph which, from 

 inducing an eruption in cows and in human beings similar to 

 that of true variola, has been distinguished by the name of 

 equine lymph, and the term equinia has been applied to the 

 eruption. The impression, in fact, that cow-pox is generally 

 due to the communication of a virus from the horse, has been 

 founded on good observations made by Jenner and his suc- 

 cessors. Mr Ceely says : " I have met with several intelli- 

 gent dairymen whose relatives had seen good reason to 

 ascribe its occurrence to the contagion of the equine vesicle, 

 communicated by the hands of the attendants of both animals, 

 but very little of that disease has been noticed of late years, 

 though I know of several farriers who have been affected 

 from the horse, and resisted subsequent variolation or vacci- 

 nation, and have seen a few who distinguish between the 

 equine vesicle and the grease, a recurrent disease eczema 

 impetiginodes as it appears to me." 



I have always described two forms of grease in the horse: 

 the one in which the lymph was capable of inducing a well- 

 marked eruption in man, and the other very similar in 

 character, but unassociated with the development of a specific 



