the Teeth of graminivorous Quadrupeds. 243 
“ While the teeth are within the gum, there is always a muci- 
*« laginous fluid, like the synovia in joints, between this mem- 
“ brane and the pulp of the tooth.” * 
This mucilaginous fluid, I have already asserted, deposits the 
enamel ; which is further confirmed by the following experi- 
ments and observations. 
The complex tooth of the elephant, being composed of three 
different structures, each of which has a peculiar process for its 
formation, led to an inquiry whether the materials themselves 
were different, or only differently arranged. 
To investigate this, Mr. Charles Hatchett, from a zeal to 
promote the pursuits of science by which he is distinguished, 
obligingly gave his assistance, and made some experiments, the 
results of which are as follows. 
It is to be understood, that a complete analysis was never 
intended to be made; as neither Mr. Hatchett’s time admitted 
of it, nor did it appear necessary for the object of the present 
inquiry. 
Experiment 1. Some enamel, rasped into a fine powder, was 
put into a matrass, and, pure muriatic acid being added, the 
whole was suffered to remain without the application of heat 
during one hour ; in the course of this time, the enamel was 
completely dissolved, with a gentle effervescence. 
To this solution, some sulphuric acid was gradually added, 
till all precipitation had ceased : the precipitate was separated 
by a filter, and was found to be selenite. The filtrated liquor, 
by evaporation, afforded a small additional quantity of selenite, 
which was also separated ; after which, the liquor, being evapo- 
porated, became thick and viscid. This, when diluted with 
• Natural History of the Human Teeth, by John Hunter, p. 86. 
