160 TKICIIOLOG1A MAMMALICM; 



Why, then, hesitate to acknowledge two species of Sheep, (lie race of one of which is 

 permanently covered with hair, and that of the other as permanently covered with wool! 

 Especially if, as has been shown, the difference between these integuments is not 

 merely one of color and marking, (as in the cases of the Horse and the Ass, and the Hor?e 

 and the Ass and the Zebra,) but where the shape, direction and inclination of the pile is 

 different where the disposition of the coloring matter is remarkably different; and, above 

 all, where the number, shape, position and mode of adherence of the scales of the cortex 

 are so entirely different as to render the one altogether unfit for felting and fulling, and 

 not liable to shrink, while the other is admirably adapted to felting and fulling, and liable 

 to shrink. Take all these things into consideration, and then say whether there is not, at 

 least, as much ground for believing these two animals to constitute two species, as there 

 exists in regard to the unity or plurality of the humps of the Camel, or of the horns of 

 the Rhinoceros. And then, again, remember that, to establish this modification, there 

 must he a difference of organization a difference in the functions which the apparatus of 

 each kind have, respectively, to perform; for instance, the fibres and cortex of the wool, 

 while they subserve all the ordinary purposes which they do in hair, are also the medium 

 of conveyance for the coloring matter of the former integument, while that of the latter 

 flows in a central canal. 



" Species of plants (says Mills) are not only real kinds, but are, probably, all of them 

 real lowest kinds, or infinae species." And he adds, "I say probably, (not certainly,} 

 because this is not the consideration by which the botanist determines what shall or shall 

 not be admitted as a species ; but which, consistently with experience, might have been 

 produced from the same stock."* 



So that, in the present instance, (seeing that the same law prevails in the animal com- 

 monwealth,) where the inquiry is " whether the hairy Sheep and the woolly Sheep are or 

 are not two distinct species?" we are not bound to show, absolutely, that they are 

 descended from different parentages ; but only that, consistently with experience, they 

 might have been descended from different parentages. And after having shown the diffe- 

 rence between hair and wool, and having pointed out the character of the discrepancies 

 upon which zoologists have been in the habit of creating species, we would confidently 

 inquire, whether any naturalist who had presented to him two newly -discovered wild 

 animals, otherwise alike, but one of which had always produced wool and the other one 

 hair, would hesitate to consign them to two specific departments? And if he would not, 

 then why, in the case now before us, should we allow habit, born in ignorance and 

 nurtured in stubborness, to prevail over the dictates of reason and experience? 



Let it not be supposed, from what has been hitherto said, that too little attention has 

 been paid to the laws of physiology, for we do not believe, that the zoological and physi- 

 ological, and even the embryological meanings of the word species materially differ. The 

 author last cited remarks that, "It seems to be a law of physiology that animals and plants 



* By the adoption of this rule uo inconsistency is introduced, for, (as this learned author shows,) this distinction in most 

 (and probably in all) cases happily accords with the other. 



