THE RATE OF GROWTH IN THE HORSE 287 



In the case of the horse, as in the case of the elephant, the dwarfing 

 was undoubtedly due to unfavourable surroundings. If the external con- 

 ditions were sufficient in, geologically speaking, a comparatively short time 

 to dwarf the horse until it was actually smaller than the " fossil horses" of 

 the remote Eocene epoch, it is not surprising that man with his wonderful 

 control over nature is able even in a single generation to modify greatly 

 the horse and other domestic animals. That in a few centuries the large, 



O ' 



highly-nervous race-horse, with his wonderful speed and courage, has been 

 evolved out of Eastern and native ponies is a matter of history, and every- 

 body knows that while some are now engaged in breeding pigmy horses 

 little over 30 inches in height, others are as successfully breeding huge, 

 powerful animals as wonderful in their way as their pigmy relatives. It 

 may even be said that a recognized part of the breeder's work consists in 

 modifying, through changes in the external conditions, the animals to 

 which he happens to devote his special attention, just as horticulturists, 

 by food, heat, and timely shelter, alter plants until all resemblance to their 

 wild stock is as good as lost. 



Breeders of Shetland and polo ponies, and, for that matter, breeders 

 of race and heavy horses, know well enough that to have any chance of 

 success they must exercise the utmost vigilance over the conditions under 

 which their foals, colts, and fillies are reared. Hitherto, as far as I can 

 learn, breeders have not had at their disposal any very accurate informa- 

 tion as to the rate of growth of horses either during development or after 

 birth, and hence, though aware that growth is rapid during the first year, 

 they have been without any certain index as to when changes in the food, 

 temperature, &c., are likely to produce the maximum effect. 



Having for some years been collecting data bearing on the development 

 and rate of growth of the horse, I propose now placing on record such facts 

 as are likely to prove interesting and suggestive to breeders, and to lead, 

 perchance, to the influence of various kinds of treatment before and after 

 birth being systematically investigated. In studying the rate of growth of 

 the horse, it is hardly necessary to point out that on the one hand allow- 

 ance must be made for the influence of the external conditions, and on the 

 other for hereditary influences, i.e. the stereotyped changes ultimately due 

 to the environment. In other words, that in an investigation of this kind 

 the surroundings should be as natural as possible, while the animals used 

 should neither be characterized by an hereditary tendency to produce 

 either very large or very small offspring. Bearing these points in mind, 



1 selected for observation the offspring of horses from 14 hands to 14 hands 



2 inches in height the height at times reached by horses living in an 

 almost wild state in the west of Ireland and I provided the foals and 



