108 



Hereditary Diseases of Horses. 



constitution, to gentle and tractable as to fiery and indomitable 

 disposition. The size, weight, general appearance, expres- 

 sion of countenance, fleetness, and temper of the horse are 

 all hereditary. Many illustrations might be given of parti- 

 cular families being remarkable during several generations for 

 good or bad points^ as for well or ill-formed head ; for high and 

 well-developed, or for low and weak withers ; for fine, strong, 

 and well-turned, or for coarse, weak, and ill-formed limbs. 

 Peculiarities of colour often extend through many generations, 

 and are so constant in their transmission as sometimes to form 

 one of the distinctive characteristics of a race. Indeed, most 

 breeds of horses have a prevailing colour, to which there are few 

 exceptions. The heavy horses of Lincolnshire, for example, are 

 generally black ; the Cleveland, bay ; and the wild horses of 

 the plains of Eastern Siberia, dun. Particular markings, also 

 — as white spots on various parts of the body, stars and blazes on 

 the face, one or more white feet or legs — often continue for 

 many generations peculiar to certain families. 



The general constitution of an animal is no less hereditary 

 than the external qualities to which we have just alluded. Some 

 stocks of horses, for example, can sustain with impunity an 

 amount of labour which, in others of the same breed, would 

 cause serious bad effects ; and the peculiar action both of medi- 

 cines, and of morbific causes, is generally observed to be similar 

 in members of the same family. But besides the general con- 

 stitution of the parents, their special condition at the time of 

 copulation also appears to be to a certain extent transmitted to 

 the offspring ; and hence the necessity of selecting for breeding 

 purposes only animals of a strong and healthy constitution, and 

 of using them only when they are in full possession of all their 

 physical energies. For a high state of the physical energies at 

 the time of impregnation is believed to induce a correspondingly 

 great development of physical power in the offspring ; and of 

 this we have a curious example in the fact, that the Arabs, before 

 bringing the parents together, give them a short gallop, believing 

 that the spirit and fleetness of the progeny is thereby enhanced. 

 On the other hand, we find that even a slight and temporary de- 

 bility at the time of copulation exercises a marked deteriorating 

 effect upon the spirit and vigour of the offspring, and it is well 

 known that the stock of old stallions is generally weak and spirit- 

 less : " Senes valetudinarii, imbecilles . . . filios vitiosa consti- 

 tutione gignunt." — Fernel. 



It must be observed that external circumstances, as diet and 

 temperature, exercise a powerful influence on animal growth and 

 development. With meagre fare and exposure to cold, animals 

 do not reach the average size of their race, and beget stock as 



