[74] In one of Dr. Priestley’s papers above quoted he says, that _charcoal_ is entirely of _vegetable_ origin; but the conversion of vegetable into animal matter which we daily see is an undoubted proof that there cannot be any essential difference between them. Even the bones are undoubtedly produced from vegetables in such animals as feed upon vegetable substances; so that even the calcareous earth they contain is plainly of vegetable origin. We may say indeed that the calcareous particles had a previous existence in the vegetables used by the animal as food; but we may say the same of the particles of the blood, flesh, horns, &c. Besides, Dr. Priestley has shown that _every_ particle of charcoal may be volatilized into inflammable air, with as great accuracy as any human experiment can be made; so that in this case the calcareous particles, if any such there were, showed themselves to be as much charcoal as the rest. In the 74th volume of the Philosophical Transactions, Mr. Watt has shown, that dephlogisticated spirit of nitre may be changed into the smoking and phlogisticated kind by means of red-lead or magnesia alba, as well as by charcoal; of consequence there can be no essential difference even there. In short, so wonderful and multifarious are the transforming or metamorphosing powers of nature, that every attempt to find out a substance upon which these powers cannot act, will be found altogether vain, and our best conducted and most plausible experiments, made with a view to discover the ultimate composition or what we call the elements of bodies, will be found mere inaccuracy, bungling and blunder.