The other anæsthetics named induce similar stages, and deaths from them occur in much the same relationship in so far as stage is concerned. It is an exceedingly difficult matter to account, in many instances, for death under anæsthetics. There seems to exist at all times in the population a certain number of persons who are, if I may so express it, predisposed to succumb under the influence of narcotic vapor. In certain of these the reason of the tendency is clear enough after death, for they are found to have fatty degeneration of the heart, of the brain, of the kidney, or some degeneration of the blood-vessels. But in other instances no such changes as these are discoverable, and although the physician is sometimes able to say in respect to some who are about to undergo operation, that general anesthesia is imprudent or unsafe, there is a greater number in whom it is unsafe, although they present no reliable grounds for such prediction. Speaking generally, persons who are hard drinkers; persons who are suffering from decided indications of fatty degeneration of the heart; persons who have signs of obstructed circulation, such as large and varicose veins, or dropsical swellings of the feet; persons who have had apoplectic threatenings or seizures; persons who have evident symptoms of Bright's disease of kidney; persons who have intermittency of the pulse; and persons who are exceedingly emotional and nervous, are bad subjects for general anæsthesia. A great many more anæsthetics than those I have named have been employed for short periods and in what may be called an experimental way, and various admixtures of anæsthetics, such as ether and chloroform, ether and methylene, ether chloroform and alcohol, have been similarly used. But, the general tendency of practice is towards demand for a single anæsthetic which shall act without variability. A perfectly safe and convenient general anesthetic remains still to be discovered. CHAPTER I. ACQUIRED DISEASE FROM MENTAL AGENCIES. AMONGST the induced or acquired conditions of disease, or diseases incident to human kind, are those which spring from mental influences, and which are due to something done through the mind of the affected person himself, or by some one or something outside himself. By virtue of his higher mental organization, man differs from the inferior animals in relation to the classes of disease which are now under our consideration. The difference is one which is not altogether in his favor, and which is very distinctive in respect to him. He shares with the animal world generally in regard to the influence of the animal appetites on his physical nature. He shares with many of the higher classes of animals in regard to the influences of fear, rage, jealousy, and those faculties of mind which we call the passions. But he is subjected to other influences which are exclusively his own, and which belong to his peculiar moral, intellectual, and habit-forming characteristics. Man, consequently, derives, through mental agencies, a number of diseases, physical and mental, which cannot strictly be said to belong at all to the lower forms of animal life. More than this, in respect to some of the very influences which affect them equally with him, under certain circumstances, he has what they have not, a special gift of foreknowledge, which causes him to be affected by the anticipation of what is to happen, or what may happen, and which anticipation may be to him as severe as the actual occurrence of what is expected. We have then, in dealing with man, to consider a number of induced symptoms or diseases which, brought about purely by mental influences, are also brought about by such subtle influences that it is very difficult to trace the effects up to their cause. difficulty is rendered greater by the circumstance that physical The |