ON MAN AND ANIMALS. 39 
powerful aid of its enlightenment to fill up a void so repugnant to 
the progress of science. 
Without advancing too far, let us simply narrate here some 
facts tending infallibly to prove the great influence climate exerts 
on horses. 
The horse of South America, imported from Spain three centu- 
ries ago, bears no resemblance to the Andalusian horse. The 
French horses that were taken to Camargue are become small, 
and exclusively white or grey. All English horses brought to the 
continent quickly with us degenerate, in spite of every care that 
can be taken of them. Colts reared in their native land become 
completely altered under the influence of climate. Normandy every 
day furnishes proofs of this in the colts of Bretagne and Poitou, 
which are reared in its rich pasturages, and afterwards sold as 
Norman. 
Thus it is, in inquiring into the influence climate exercises over 
the individuality of different breeds, that it affects their powers, 
and renders them fitted for different purposes. 
The same likewise explains how all attempts, up to the present, 
made with a view of ameliorating indigenous breeds of horses by 
the introduction of foreign blood, have constantly miscarried. 
Influence of the Seasons , of Temperature , and of Soil , on Exercise. 
1. In winter, when the cold does not exceed 15°, it proves ex- 
citive of action, accelerates it, increases the power of the muscles, 
and is favorable to the plastic process ; but more intense than this, 
it operates against action, and by the torpor it engenders, against 
prolonged great speed, as well as against exercises requiring any 
great suppleness, as, for example, that of the school. Cold, by 
stimulating the plastic power, diminishes the sensibility and flexi- 
bility of the muscular fibre. 
Consequently, winter is a fitter season for moderate exercises, 
though these may be long sustained, than for rapid evolutions. 
And so the highly schooled horse will shew less suppleness and 
less brilliancy during severe cold than at the time when the tem- 
perature is mild. We have often made the remark, that horses 
leaping of their own accord, who ordinarily would clear seven feet 
in height with astonishing facility, could not perform the same feat 
in winter, though ridden, not by any learners, but by ourselves. 
2. In the spring, the horse requires some management at the 
time he is changing his coat; though beyond this, this is the 
season when the animal is most nimble, and best undergoes all 
sorts of fatigue. Immediately after he has changed his coat he 
enters on a period wherein all his powers become, as it were, re- 
