HEREDITY OF DISEASES. 29 



had ring-bone, to a greater or less extent, and several 

 were entirely disabled. 



In horses, strain of the back-tendons, swelled legs, 

 grease, and roaring, are often hereditary ; while a pre- 

 disposition to rheumatism, malignant and non-malig- 

 nant tumors, chronic cough, ophthalmia and blind- 

 ness, epilepsy, and a great variety of nervous disorders, 

 is inherited by them in common with cattle, sheep, 

 and swine. 1 



Lucas says, " A blind beggar was the father of four 

 sons and a daughter, all blind. Dufau, in his work 

 on c Blindness,' cites the cases of twenty-one persons 

 blind from birth, or soon after, whose ancestors fa- 

 ther, mother, grandparents, and uncles had some 

 serious affection of the eyes." a 



According to M. Trehonnais, a stallion, in France, 

 became blind from the effects of disease, and all of 

 his progeny had the same defect before reaching the 

 age of three years. 3 



Dr. Dun says that "a very large number of the 

 stock of the celebrated Irish horse Cregan have be- 

 come affected by ophthalmia of the worst kind. I 

 am told by a gentleman well acquainted with this 

 stock that the tendency is still decidedly marked, even 

 in the fourth and fifth generations, often appearing, 

 and sometimes speedily causing blindness very early 



1 " Encyclopedic Pratique de PAgricuIteur," tome viii., p. 678. See 

 also a series of articles on " Hereditary Diseases," by Finlay Dun, in 

 the Journal of the Royal Agricultural Society, vols, xiv., xv., xvi. 



2 Quoted from Kibot on " Heredity," p. 40. See also Darwin's 

 "Animals and Plants under Domestication," vol. ii., p. 18. 



3 " Encyclopedic Pratique de PAgricuIteur," tome viii., p. 678. See 

 also " The Horse," by Youatt, p. 115. 



