It is now to be regarded as an established fact, that Horsegrease and Cowpox are the same complaint, modified by the constitution of the animals in which they occur. An established fact, indeed!--established in quicksand! Some say the Gloucestershire farmers and Jenner were correct in attributing Cowpox to Horsegrease, and that they can only he charged with mistake in nomenclature. When they said Horsegrease, they meant Horsepox, not discriminating between maladies that sometimes occurred together. No one now believes that the affection recognised by veterinarians as “grease” ever originated Cowpox. The same rural authorities, including Jenner, held that where there was no Horsepox, there could be no Cowpox; but, so far as I can make out, that conclusion is surrendered. Pox on the horse may generate pox on the cow, but the cow may have pox without the horse. In this respect only was Jenner in error [says Mr. George Fleming, Army Veterinary Inspector]. The two diseases are perfectly independent of each other. Cowpox appears where there are no horses, or possible contact with horses; and may affect a number of cows in a dairy while the horses are entirely free from Horsepox.[159] At this point comes the tug of war. If cows have pox, how do they contract the malady? Speaking at the London Conference on Animal Vaccination in December, 1879, Professor J. B. Simonds, Principal of the Royal Veterinary College, said-- My contention is, that the existence of Cowpox has to be proved. Jenner’s account of the disease was an illusion. In my experience among animals for forty years, I have never seen a case of Cowpox, and I do not believe that any form of variola belongs to the bovine race. Sheep are afflicted with pox, but not cattle. We hear of Cowpox, but who ever heard of Bullpox? And is it credible that a disease should be confined to cows and never attack bulls and steers? Let any one point out an affection of females that does not extend to the males of the same species. Professor Simonds and others believe that Cowpox as described by Jenner was a parasitic affection of Smallpox, probably communicated by milkers; and that Ceely, Badcock, and others did intentionally, what milkers had done inadvertently, when they inoculated cattle with Smallpox in order to create virus for vaccination. On the other hand, those who assert the independent existence of Cowpox, hold no terms with this heresy. As Dr. Cameron says, “We can no more make Smallpox into Cowpox than by stunting an oak-tree we can make it a gooseberry bush.” Fortunately I have no call to pronounce judgment on the controversy. The more it rages, the better I like it, and if the combatants disposed of each other as did the Kilkenny cats, I might not be very sorry.