Some experiments which I lately made at the request of Mr. Home, and which he has done me the honour to mention in his ingenious Paper on the teeth of graminivorous quadrupeds, induced me to turn my attention more particularly to the chemical examination of shell and bone, especially as the former appeared to have been hitherto much neglected. The time since these experiments were began, has not been sufficient to enable me to enter into all the minutiæ of the chemical analysis of these substances; but, as some remarkable facts were ascertained, I have now ventured to bring them forward, with the addition of some observations, although, as yet, the whole is little more than a very imperfect outline.