652 
GREASE. 
much trouble. If the coronet become swollen, the horn below must be 
rasped away. 
A common sequel of gangrene is the formation of sinuses just above 
the heels, in consequence of a necrotic piece of tissue being retained in 
the depths, and keeping up chronic inflammation and pus formation. 
The passage of a sublimate seton, or the injection of liquor Villati, is 
sometimes sufficient to procure healing, but in obstinate cases it may be 
necessary to freely lay open the parts. 
(4) Dermatitis chronica verrucosa. “ Grease ” proper. This condition 
is always chronic and progressive. 
Originating in a small spot in the fetlock-joint, the process gradually 
extends until it may involve the entire carpal or tarsal joint. In other 
cases a considerable area may be attacked at the outset. It is due to 
active proliferation in the rete mucosiun ; the cells produced, however, do 
not become horny, but break down and form a fatty, ill-smelling, grey 
mass on the surface of the diseased skin. In less rapidly progressive 
forms the cells form a grey, mealy mass. The more intense the process, 
the more active the proliferation, and the more abundant the exudation 
which bathes the surface of the skin. The papillae at the same time 
increase in size, so that they appear like warts, and may generally be 
recognised by the naked eye; sometimes they become as large as a pea. 
The deeper layers of the cutis, and even of the subcutis, take part in the 
process, producing marked elephantiasis. The process extends to the hair 
follicles ; the hairs are mostly shed, and the few which remain stand erect. 
Leblanc in 1850 made microscopical examinations of the diseased skin, 
and regarded the condition as a simple hypertrophy. He found the hair 
follicles and sebaceous glands enlarged. In another section it has been 
pointed out how closely this process resembles canker. Either disease 
may extend to new structures, giving rise to the other ; thus grease may 
produce canker, and canker grease. 
The disease is more frequent in the hind feet, particularly in hairy- 
legged horses like Clydesdales; sometimes it seizes on several feet, one 
after the other. Whether a specific organism is the causative agent 
remains for the present undecided, though such an explanation appears 
probable. Sometimes the disease originates from the eczematous form 
of dermatitis; not infrequently it is due to slight grazes or scratches. 
Holler saw many outbreaks of this form of grease in certain stables ; 
indeed, there seems to be some ground for referring them to direct infec¬ 
tion. In large establishments animals in hospital were often attacked 
after being rested for some time, and in one case the horse-keeper suffered 
from an eczematous disease on the hands. Every practitioner has noticed . 
how the disease is transferred from the affected leg to the sound one by 
rubbing. The local appearances and gradual spread of the disease point 
