114 STUDIES IN ANIMAL LIFE. 



sented by the staghouijd. These staghounds would 

 transmit to their offspring all their specific charac- 

 ters. But, as every one knows, however much dogs 

 may resemble each other, they always present in- 

 dividual differences in size, color, strength, intelli- 

 gence, etc. Now, if any one of these differences 

 should happen to become marked, and to increase 

 by the intermarriage of two dogs similarly distin- 

 guished by the marked peculiarity, this peculiarity 

 would in time become established by hereditary 

 transmission, and would form the starting-point of 

 a new race of dogs — say the greyhound — unless it 

 were obliterated by intermarriage with dogs of the 

 old type. In the former case, we should have two 

 races of dogs iamong the descendants of those fig- 

 ured on the Egyptian tombs ; but as one of these 

 races would still preserve the original staghound 

 type, Cuvier would refer to it as a proof that spe- 

 cies had not varied. We, on the other hand, should 

 point to the greyhound as proof that animal forms 

 are variable, and that a new form had arisen from 

 modification of the old. 



An objection will at once be raised to this illus- 

 tration, to the effect that all zoologists admit the 

 possibility of new varieties or races being formed ; 

 but they, deny that new species can be formed. It 

 is here that the equivoque of the word species pre- 

 vents a clear understanding of each other's argu- 

 ment. Whiteness may justly be said to be unalter- 

 able; but white things may vary — they may be- 



