384 DISEASES OF BEEATHIKGr. 



country-breds, especially stud-breds, were over 15.2. I have known 

 two or three instances of roarers Avhich were imported from 

 Australia into India become perfectly sound in their wind, after a 

 residence of a year or two in that hot country; a fact which 

 shows the strong influence of climate in this disease. It is evident 

 that such a recovery is possible only during the early stages of 

 roaring, before any marked structural change has taken place in 

 the affected part (the laiynx). Roaring affects about 5 per cent, 

 of all the horses in England. In Australia, probably not 1 per cent, 

 of the horses are wrong in their wind. In the United States, the 

 percentage is less than in this country. 



Although, the fact of Ormonde being a roarer, was the apparent 

 cause of his not being retained in this country as a sire, M. Ed. 

 Nocard (" Receuil Veter.") tells us that none of the stock which 

 he sired in Argentina went wrong in their wind. 



My experience in the interior of Russia convinces me that damp 

 greatly increiases the predisposing influence which a cold climate 

 has on roaring. It has no effect in this respect, in the case of hot 

 climates. The same remark applies to the influence of climate 

 in producing coughs and colds. 



2. Heredity, especially in the dam, has a very strong predisposing 

 influence in cold, damp climates, but an extremely weak one in hot 

 countries. I found in India and South Africa that the fact of a 

 dam or sire being '' musical," was practically no detriment to his 

 breeding value. The only positive case of hereditary predisposition 

 in roaring which I met with in India, was a thorough-bred two-year- 

 old colt whose dam, an Australian, was a roarer. On putting him 

 into work, I noticed that he made a noise, but he became perfectly 

 sound in his wind before he was three years old. 



The only proof we have of heredity being a cause of roaring is 

 furnished by some authorities who aver that they have met with 

 cases in which the left recurrent nerve was absent at birth. Such 

 instances are so rare, and have been so imperfectly authenticated, 

 that we may regard a predisposing influence as the only part 

 played by heredity in the production of roaring. 



Breed^ as a factor in roaring, comes under the heading of heredity. 

 Of all races of horses, the English thorough-bred is most liable 

 to acquire the paralytic form of roaring, a predisposition which is 

 more or less inherited by its descendants. The chief reason for this 

 characteristic liability is that this breed has suffered during a long 

 succession of years from causes best calculated to establish a strong 

 hereditary predisposition, namely : residence in a cold, damp cli- 

 mate; living, in many instances, in heated and ill-ventilated 

 stables; being constantly fed on dry, hard food; and being habi- 



