TRANSMISSION OF DISEASE. 103 



than those giving rise to disease, and a transient disease is not 

 likely to affect any of the progeny, but those in embryo at tfhe 

 time of its existence. Diseases with a constitutional taint, on 

 the other hand, are transmitted from grandfather to grandson, 

 though the intervening generation may have escaped. 



As regards accidents and transient diseases, thougli the pit- 

 ting of smallpox, the absence of limbs from amputation and the 

 like, are not hereditary, yet the accidental loss of the tail in the 

 dog, cat and horse, has determined an offspring void of tails, or 

 with short ones. A cow which lost her horn, with suppuration, 

 afterwards, had three calves hornless on tlie same side of the head 

 (Prosper Lucas). A pregnant mare of Mr. Socrates Scott's, 

 Dryden, N Y., had a severe inflammation of the left eye, sup- 

 posed to have been caused by a burdock in the forelock. She 

 remained blind till after the birth of a filly, and subsequently 

 entirely recovered. The filly, now a nine year old mare, has 

 the lefc eye undeveloped, represented by a small black mass 

 about the size of a field bean, and quite opaque. The dam, after 

 having recovered her sight, bore four colts with perfect eyes, and 

 the mare with the undeveloped eye has equally given birth to 

 several whose eyes were sound. Brown-S^quard found that 

 Guinea pigs, in which he had produced epilepsy by an operation, 

 afterwards brought forth litters subject to the same malady, — 

 which is otherwise very rare in this species. Unusual as such 

 cases are, they show the greater tendency to transmit a defect 

 when accompanied by disease. Those diseases that are habit- 

 ually transmitted are much more important. 



The specific inflammation of the eyes in horses is notoriously 

 hereditary. Its prevalence in England is much more limited 

 than it was fifty years ago, when less care was taken by breeders 

 to reject animals the subjects of this infirmity. In many parts 

 of Ireland and America blindness seems to doom a mare to 

 breed, mainly because she is less fit for anything else ; and I 

 regret to say that blindness is a remarkable feature of the Irish 

 and American horses alike. Stop the stream at its fountain and 

 in ten years the land would be stocked with a sounder eyed and 

 more serviceable horse. 



I knew a Clydesdale mare with feet preternaturally small, and 

 kept tender by faulty shoeing, and of her four foals two had feet 

 so small and weak that they were practically useless, while the 



