92 
KUMINATING ANISrAT.S. 
only last for a season, the different stages of their 
formation can be readily traced ; and when they are 
completed, and tlie supply of blood is withdrawn, the 
process of exfoliation, by means of which they drop 
off, is a beautiful illustration of that operation. 
In their growth, the first change that takes place, 
is a very considerable enlargement of the arteries 
leading to that part of the skull ; then the horn, as 
it is termed, begins to shoot. In the early stages, 
it is a vascular cartilaginous structure, covered with 
a velvet-like cutaneous covering. The cartilage is 
gradually converted into bone; and when this pro- 
cess is completed, the covering becomes so thin, 
that it is readily rubbed off by friction in the use of 
the horn. 
“ As soon as the horns become hard, the blood- 
vessels going to them gradually diminish in size till 
the horns are deprived of all support, after which 
they are exfoliated like any other dead bone. This 
is perhaps the most beautiful instance in nature, of 
a bone being formed for a temporary use, and cut 
off by absorption, as soon as the purpose is answered 
for which it was intended : the use of the velvet-like 
covering is evident, as it corresponds to the perios- 
teum of other bones, being tbe medium through 
which the nourishment is received ; and as soon as 
that is separated, in both cases death takes place. 
“ That this weapon of defence in the male of the 
deer kind should owe its growth, and its decay, to 
the state of the organs of generation, is a very ex- 
