HEREDITARY DISEASES OF HORSES. 
637 
hair about the heels, and the formation of deep cracks and 
fissures ; and sometimes becoming so violent and inveterate, 
as to cause aversion of the sebaceous glands, formation of 
granulations, and secretion of pus, constituting the loath- 
some complaint termed the grapes* There are few diseases 
better deserving the epithet of hereditary than grease, and 
few in which the hereditary nature can be more easily 
discovered and traced. Almost every practitioner can bring 
to his recollection cases showing the tendency of this disease 
to descend from parent to offspring. A friend of mine some 
years ago purchased a valuable four year-old entire horse, 
adapted for agricultural purposes. When bought, he ap- 
peared perfectly sound, and his limbs were nearly black, well 
formed, and fine ; within a short time, however, they became 
thick and greasy. And, although the mares to which he was 
put were perfectly free from such faults, the progeny have 
shown, in every case where they can be traced, unmistakeable 
evidence of their inheriting the greasy diathesis of their sire. 
They have all been found liable to swelled legs when they stand 
idle for a few days, most of them have been the subjects of 
repeated attacks of weed, all are affected, particularly in 
spring, with scurfiness of the skin of the hind extremities 
and excessive itchiness, and lose at a very early age their 
flatness and smoothness of limb. The faults occur to a 
greater or less degree in all the stock of this horse by many 
different mares, and are distinctly traceable to the third 
generation. But, although grease is undoubtedly hereditary, 
and is therefore readily induced by comparatively simple 
causes, still it is frequently caused, and is always aggravated, 
by neglect of cleanliness, and of this there is ample evidence 
in the fact, that it is most common in foul and badly man- 
aged stables, and where no pains are taken to keep the 
horses’ feet and legs clean and dry. 
Inflammation is of two sorts, common and specific. These 
differ from each other in their symptoms, their progress, and 
their termination. Common inflammation is accompanied 
by effusion of lymph and suppuration, has usually a par- 
ticular seat or locality, is tolerably regular in its course, and 
tends to a healthy termination : none are exempt from its 
attacks, and it is seldom hereditary. It is exemplified in the 
healing of wounds, and in the so-called phlegmasiae, as pneu- 
monia and pleurisy. Special or specific inflammation, on 
the other hand, has peculiar symptoms, is not necessarily 
localised, but may affect more or less the whole system, is 
very variable in its course, not easily subdued by remedial 
measures, and seldom entirely cured ; not easily produced 
