dup- PROFESSOR OF ANATOMY, PHYSIOLOGY, AND PATHOLOGICAL ANATOMY IN KING'S PHILADELPHIA: PRINTED BY ADAM WALDIE, 46 CARPENTER STREET. INTRODUCTION. OF DEATH; AND OF THE ELEMENTS OF PATHOLOGAL STUDY. There is a life, which is simply vegetative. This is displayed in plants, and in molæ or imperfect conceptions of animals. It consists in nutrition; that is to say, in the performance of certain actions in which the individual imbibes, and assimilates, and distributes through its frame, foreign matter, with the double end of preserving itself against the destroying influence of external agents, and of producing other similar beings to perpetuate its species. The death of vegetative life is the cessation of nutrition: a time arrives, when foreign matter is no longer imbibed and assimilated, and when the organised body yields to decay. Animal life is vegetative life, and something more. An animal, like a plant, grows by nutrition; but besides the organs employed in assimilation and secretion, it has others [formed in it by the same principles of growth as the assimilating organs] in which, through a mysterious union, sensation and volition, instinct and reason, temporarily reside. Of these organs in the higher animals, and in man, the brain is the essential one: the extinction of the function of the brain is their DEATH; whether we regard man, whose death is the separation of the body and of an immortal soul—or animals, whose death is the suppression of a narrower consciousness. When we examine the varieties of cerebral lesion or impairment, that are sufficient to put an end to consciousness, they are found to be reducible to eight distinct heads:-mechanical or chemical injury-mental shocks-direct action of certain poisons on the brain-deficient momentum in the circulation of arterial blood in the brain-circulation of black blood in the brain-collapse following over-excitement-deficient nutrition-sympathy with lesions of other parts. I. Mechanical or chemical injury. a. Concussion of the brain, if sufficiently violent, is instantaneously fatal, through direct extinction of cerebral power. b. Partial laceration of the upper part of the medulla oblongata is capable of destroying life at the instant. This is proved by the following experiment. Cold-blooded animals have a wonderful tenacity of life, and retain sensation and volition for a considerable period after the heart |