ANIESTHETICS.—Agents which can cause a loss of sensibility (see The introduction of general anaesthesia in medicine may be accounted one of the greatest of all scientific accomplishments. That it should be possible to do the most extensive operations without causing the least pain must be looked upon as a technical advance, with which scarcely any other, electricity and steam included, can be compared. The agents most commonly used are the vapours of ether, chloroform, and laughing-gas. These vapours are taken up by the blood through the medium of the respira tory organs, and are carried to the brain and spinal cord, where they inhibit the action of those particular nerve-cells which together control conscious ness. So far as the actions of ether and chloroform are concerned they may be compared with the pharmacological action of alcohol, inasmuch as both are derivatives of the marsh-gas series and are chemically closely com parable with alcohol. The effects are practically the same, the important difference being one of time. As ether and alcohol are lighter and more readily diffusible, their action is more rapid. The action may be sum marised as follows : At first there is a diminution in the functioning of the higher faculties, these being, as it were, separated from the rest of the ner vous system and rendered inoperative ; then the functions of voluntary action disappear ; the sensations become dimmed ; sight, hearing, touch, and taste fade away ; the incoming paths of sensations are cut off, and the simplest reflexes are diminished or abolished until finally the patient is reduced to those reflexes which are of the most fundamental character and without the action of which life-processes cannot be maintained—namelv, the breathing and the heart-beat.
The fact that sensation is suspended during narcosis brings with it certain risks ;. thus, mucus cannot be coughed up, nor can vomit be expectorated. This endangers respiration, and, although it is necessary for the anaesthetist to combat these conditions, the patient himself may do much to reduce the chances of any trouble taking place. It is well to starve oneself
for twenty-four hours previous to an operation, and to provide for free evacuation of the bowels. This does not produce weakness ; on the con trary, by completely emptying the stomach and intestines, the respiratory activity will not be embarrassed. The life of the narcotised person depends on keeping up a regular respiration. The patient must also endeavour to overcome the excitement natural to such an occasion, and thus to spare the heart ; for the increased cardiac activity necessarily brought about by such excitement will do more to weaken the individual than is ordinarily supposed. There is one important factor in preparing for an operation, and that is complete and thorough confidence in the physician who holds the patient's life in his hands for the time being.
There is no greater reward for the operator than the confidence which he sees expressed in the patient's face as he is about to perform an opera tion, and which spurs him as a direct and earnest appeal to his best know ledge and abilities. On the other hand, there is no more valuable asset to the person who is about to trust his life to the care of the surgeon than this same feeling of composure and confidence in the latter's abilities. After the operation, the extreme nausea may be partially overcome if the patient will convince himself by a strong effort of the mind that it will soon pass over. Inhaling the fumes of vinegar %vitt afford a great deal of relief. No food or drink should be taken during the first few hours. It is well to keep as quiet and flat as possible and not to get up when vomiting. The after effects of an vertigo, and a bad taste in the mouth --soon disappear. That more severe disturbances might occur, lasting weeks or months, is an unnecessary source of worry, as these have never been definitely substantiated. For local anesthetics, see COCAINE.