THE ANTLERS. 177 
tween the old and the new bone, for the internal supply of nutri- 
ment. 
But this is not all. Copious as is the supply of blood which 
these great arteries are capable of furnishing, still it is inad- 
equate for so rapid a growth; so we find another set of blood- 
vessels, communicating directly between the persistent and the 
deciduous osseous formations. These pass up through the body 
of the pedicel into the antler, and together with those just de- 
scribed, perform the office of the medullary artery in the internal 
long bones, supplying it with nutriment internally, and commu- 
nicating, as in the case of common bones, with the Haversian 
systems connected with the periosteum. Let us examine a cross 
section of the pedicel, just below the seat of the antler, when the 
antler is but half grown and the work is going on in its full 
vigor, and we find it open and spongy, apparently composed of 
pretty compact cancellous tissue towards the circumference, but 
with open canals near the middle. In the specimen now before 
me, which is cut across, one of these canals is nearly one line in 
diameter. This is the largest distinct canal for the passage of 
an artery through the pedicel which I have found, but when these 
canals are smaller, there are more of them, if examined at the 
same stage of growth. These canals afford abundant passage for 
the blood-vessels passing up through it into the new-growing 
antler. 
Let us compare it with another, also on my table, on which 
the antler had become hard, and was nearly ready to be cast 
off. Now we find this pedicel, which a few months before was 
so porous, has become a compact bone throughout, with the cav- 
ities so far filled up as to collapse the blood-vessels and obstruct 
the appreciable passage of the red blood, though, of course, the 
lacunz and the canaliculi are still preserved as necessary to its 
own continued vitality; but all the visible canals are now filled 
up. Here, then, is an order of nature found nowhere else, be- 
cause the necessities of the case nowhere else require it. We 
find a persistent bone, alternately compact and porous, alter- 
nating annually, simply because it is necessary to the per- 
formance of a peculiar function, nowhere else in the whole 
range of nature’s works demanded. 
When the time approaches for the new antler to commence its 
growth, the laminze which had filled up the canals in the pedicel 
through which the nutriment to promote that new growth is to 
pass, are absorbed away and the canals are thus enlarged, and 
12 
