> 
THE ANTLERS OF DEER. 351 
ities are first completely solidified. Now occurs a phenomenon 
which does not occur with the internal bone whose conditions do 
not require it. 
At the extremities first, the deposit of earthy salts goes on till 
this fills up the canals leading from the periosteum to the Haver- 
sian canals, so that the circulation through them is obstructed ; 
and from these points complete condensation goes on till it 
reaches the lower extremity, when the communication between the 
external and the internal blood-vessels becomes completely sev- 
ered. Now it is that the animal is prompted bY some natural im- 
pulse to rub off this outer covering while yet it is gorged with 
blood. It comes off in long strips or shreds, which look like red 
cords suspended from the antlers and cover the animal with blood 
wherever they can reach and stain the trees and branches which he 
uses forthe purpose. During this time the animal seems excited 
and even fierce. I suppose that this impulse to rub off the velvet 
arises from an irritation created in this thick vascular covering, 
from the fact that the arteries are pouring into it their full volume 
of blood, while the imperfect venous system with which it is pro- 
vided is unable to return the blood sufficiently now that it is cut 
off from the veins within the antler which had principally per- 
formed that office before the surface canals had been closed. 
While this has been progressing on the surface, the growth within 
has been progressing also from the nutriment received by the in- 
ternal arteries. The cavities in the branches and the upper por- 
tion of the beam pretty soon become hardened, like ivory 
throughout, and the solid wall on the lower part much thickened. 
Before the central section has become solid, the nutrient vessels 
are obstructed below, and the deposit of bony particles is arrested 
while yet the larger portions of the antler are more or less porous, 
leaving what may represent the medullary canal, braced in every 
imaginable direction by thin plates of bone, constituting the walls 
of the cells, thus leaving the antler lighter, but nearly as strong 
as if it were entirely solid. The extent of this porous section 
and its density differ very much in different specimens; still it is 
present in all, to a greater or less extent. The active internal 
flow of the blood continues longer in young animals than in old, 
after the velvet is rubbed off. Sometimes the blood will flow appre- 
Ciably when the antler is sawed off near its seat, two or three 
