242 Mr. Home’s Observations on the Structure of 
enamel were beautifully distinct on the black ground ; but the 
bony part and the substance of the tooth were equally colour- 
ed, and had an uniform appearance. 
The examination of these preparations led him to believe, 
that the horse’s tooth consisted of only two substances, the 
tooth itself and the enamel. Under this impression, Mr. Hun- 
ter examined the growing teeth of the horse, and found the 
pulp rising from the jaw, and the vascular membranes passing 
down from the gum, into the spaces between the portions of 
pulp ; he was therefore led to conclude, that the pulp was for 
the formation of the tooth, and that the membranes which came 
from the gum were for the formation of the enamel. 
Having so fully explained, in the elephant’s tooth, the real 
uses of these two parts, it is not necessary to say more in re*- 
futation of this opinion, which is published in Mr. Hunter’s 
work on the teeth; but, in justice to the correctness of his 
other observations, I shall subjoin his account of the circunU 
stances under which the enamel of the. human teeth is formed, 
taken from the same work. He says, “ the pulps are surrounded 
“ by a membrane, which is not connected with them, except at 
“ their root, or surface of adhesion. This membrane adheres, 
“ by its outer surface, all round the bony cavity in the jaw, 
and also to the gum, where it covers the alveoli. 
“ When the pulp is very young, as in the foetus of six or 
“ seven months, this membrane is pretty thick and gelatinous. 
“ We can examine it best in a new-born child, and we find it 
“ made up of two lamellae, an external and an internal: the 
“ external is soft and spongy, without any vessels ; the other 
“ is much firmer, and extremely vascular, its vessels coming 
" from those that are going to the pulp and body of the tooth. 
