266 THE DEER OF AMERICA. 



That the odor emitted by these glands is left upon the track 

 of the deer may be presumed, but as the trail of other animals 

 not provided with these organs seems to be as readily followed 

 by the hounds, we may safely conclude that they are not the 

 only sources of the scent left in the track. The capacity of an 

 animal to leave a scent which may be followed by an enemy, 

 would seem to be detrimental to its safety or well being, es- 

 pecially in a wild state, but it is common to most if not all ter- 

 restrial animals. There are compensating advantages, no doubt, 

 at least to some extent, for it enables them to find companions 

 which they might otherwise seek in vain. 



Whatever may be the uses of these glands, certain it is that 

 they are very active, constantly secreting matter ; and this, in 

 everv case where I have examined the live or recently killed 

 animal, emits a pungent odor. 



I prefer rather to give the facts, than to advance or maintain 

 doubtful theories. 



The longer and the more minutely I have examined this gland- 

 ular system on the hind legs of the different species of this genus, 

 the more I have become impressed with its importance in the 

 division into or identification of species. As Dr. Gray justly 

 remarked, they are not transient, or exceptional, like the antlers, 

 but are present on both sexes and at all ages, and had he studied 

 them with care he would have added that they are as near alike 

 as possible on each individual of each species, and that those on 

 the outside of the legs, when present, are entirely unlike on the 

 different species ; so that upon an examination of the part of the 

 skin containing this gland, no one familiar with the subject could 

 hesitate to declare with certainty from which species it came. 

 Hardly any other single mark pervading so many species is so re- 

 liable as this, and certainly none of so small dimensions. The tail 

 of the mule deer, no doubt, will always declare itself, and so will 

 the foot of the caribou ; but still they vary in size even propor- 

 tionately, while this gland is so exact that from it alone one may 

 closelv approximate the size of the animal. Should I be presented 

 with a piece of skin, containing a gland similar to the one which 

 I have above described, yet differing from it, I should conclude 

 that it came from some distant country, and that other distinc- 

 tions would probably be found establishing a species differing 

 from any of ours. As, for instance, should I find one resembling 

 that on our Virginia deer, but without the white band, or es- 

 pecially with a black band around it, or one otherwise corre- 



