14 ESSAYS ON HORSE SUBJECTS 



tent from the ill-effects of concussion. A calf- 

 kneed horse is also much more likely to suffer 

 from strains. Knee-sprung, unlike the other un- 

 soundnesses given in the list of hereditary 

 troubles, is not very infrequently congenital. 

 Swan-necked horses and those with thick, coarse 

 throttles are considered to be of the formations 

 most liable to develop the defect of the wind 

 called "roaring." In Great Britain and Ireland 

 and on the continent of Europe, breeders are 

 usually very particular about avoiding roarers 

 for breeding purposes. The climatic conditions 

 there seem favorable to its development; but in 

 this country it is not nearly so much to be feared, 

 and one should not hold aloof from an otherwise 

 desirable sire on account of his being a roarer, 

 though it must be admitted that the predisposi- 

 tion to the trouble may be transmitted. The pre- 

 disposition to periodic ophthalmia or moonblind- 

 ness is handed down from parent to offspring, 

 but it is not nearly so common in this country as 

 it once was, when the sanitaiy conditions were not 

 so good; and it may be that some care has been 

 exercised in breeding, so as to avoid its propaga- 

 tion. The only appreciable evidence of a pre- 

 disposition to this unsoundness, outside of the ex- 

 istence of the disease, is the small or what is called 

 "pig eye." The writer knew a sire well that had 

 "pig eyes" but sound ones, and they remained 



