One of the former having been appointed to apply dressings to the heels of a horse affected with the grease, and not paying due attention to cleanliness, incautiously bears his part in milking the cows, with some particles of the infectious matter adhering to his fingers. This disease has obtained the name of cow-pox. It appears on the nipples of the cows in the form of irregular pustules. At their first appearance they are commonly of a palish blue, or rather of a colour somewhat approaching to livid, and are surrounded by an erysipelatous inflammation. The animals become indisposed, and the secretion of milk is much lessened.
Absorption takes place, and tumours appear in each axilla.
Thus the disease makes its progress from the horse to the nipple of the cow, and from the cow to the human subject.