8 THE GREYHOUND. 



or nothing of the ultimate composition of the various parts of 

 this system, but we judge by its manifestations that there is a 

 difference, though we are unable to detect it. In the same way, 

 we cannot, by the eye, easily distinguish between iron and steel, 

 though we know that the qualities of the two are essentially 

 different ; and the difference between the nervous system of a high- 

 bred race-horse and that of a common roadster is just as great. 

 The one will cheerfully persevere till, exhausted by fatigue, 

 he falls and dies ; whilst the other will knock up and refuse 

 to answer to the severest punishment which can be administered 

 by the whip or spur. So it is with the greyhound. If well-bred, 

 he runs till he can no longer stand, and, if not in condition, often 

 dies from his exertion ; while, if of low parentage, he will take 

 care to stop long before he has injured himself by his efforts. 

 But it may be said that this argument will apply equally to the 

 blood, and so it would, but that we have strong reasons for 

 believing that this fluid is really the same in all individuals of 

 the same species ; that is to say, as far as regards the composi- 

 tion and shape of its globules. But with regard to the nervous 

 system we find a great variation in different individuals and 

 families of the same species. If we compare the brain of the 

 bull-dog with that of the poodle or sheep-dog, it will be seen at 

 once that the volume of the former is much greater than that of 

 the latter ; yet the intelligence of the poodle is far greater than 

 that of the bull-dog, indeed it is higher than any other of the 

 canine race, and requires a considerable portion of brain for its 

 development. Now (without descending into the disputed points 



