328 Mr. Hatchett’s 'Experiments 
whole of the carbonate of lime obtained from an equal quantity 
of the solution. To prove, therefore, the presence of the carbonic 
acid, and the consequent formation of carbonate of lime, por- 
tions of the various teeth and bones were immersed, at separate 
times, in muriatic acid ; and the gas produced was received in 
lime water, by which it was speedily absorbed, and a propor- 
tionate quantity of carbonate of lime was obtained. 
Although it appears, that the principal effects during ossifica- 
tion are produced’ by phosphate of lime, yet we here see, that 
not only some sulphate, but also some carbonate of lime, enters 
the composition of bones; and it is not a little curious to observe, 
that as the carbonate of lime exceeds in quantity the phosphate 
of lime in crustaceous marine animals, and in the egg shells of 
birds, so in bones it is vice versa. It is possible, when many 
accurate comparative analyses of bones have been made, that 
some may be found composed only of phosphate of lime ; and 
that thus, shells containing only carbonate of lime, and bones 
containing only phosphate of lime, will form the two extremi- 
ties of the chain. 
I shall now make a few remarks on the enamel of teeth. 
When a tooth coated with enamel is immersed in diluted ni- 
tric or muriatic acid, a feeble effervescence takes place, and the 
enamel is completely dissolved; so also is the bony part, but 
the cartilage of that part is left, retaining the shape of the tooth. 
Or, if a tooth in which the enamel is intermixed with the bony 
substance, is plunged in the acid, the enamel and the bony part 
are dissolved, in the same manner as before ; that is to say, the 
enamel is completely taken up by the acid, while the tooth, 
like other bones, remains in a pulpy or cartilaginous state, 
having been deprived of the ossifying substance. Consequently, 
