A powerful mental emotion will blanch the surface of the body, whereas a slight one will cause a rush of blood to the capillaries, and cause a blush. How much is conveyed in this every-day occurrence! It explains most perfectly the nervous command over the circulating system. All those anaesthetic agents which act specifically on the nerves of the heart should be avoided. I have never been an advocate of the chlorine compounds for this reason. In some the action is so immediate that they are struck down as if by lightning, fortunately these cases are comparatively exceptional; still they have occurred, and exemplify a principle which runs through many phases; showing that we must seek for chemical combinations more harmonious to the vital economy, which have the property of producing anaesthesia.

Amongst these, none command attention more than the nitrous oxide, that is, one proportion of nitrogen combined with one proportion of oxygen. It is a near approach to the natural respiratory element, the excess of oxygen causing the excitement and subsequent unconsciousness. The nitrous oxide the last few years has been employed in hundreds of thousands of cases. I am not aware of a single fatal result arising from its inhalation.

On the 25th of July, 1865, Dr. Carrochan of New York removed the entire breast with the glands of the axilla, the patient being kept insensible for sixteen minutes. This distinguished surgeon also performed several amputations of the leg under the influence of the nitrous oxide. The inhalation of this gas is unaccompanied by nausea, sickness, or vomiting, or any of the unpleasant symptoms which so often accompany and follow the inhalation of chloroform.

The nitrous oxide gas will become the favourite anaesthetic. The writer, who has had perhaps as much experience as any one in the administration of all kinds of anaesthetics, would not hesitate one instant the inhaling of nitrous oxide to produce unconsciousness; he certainly would not breathe any other vapour to produce insensibility.

It is no use combating with gentlemen who start with a favourite theory. Dr. Ozanam says, "Tout la serie des corps carbones volatile "on gazeux est douee du pouvoir anesthetique; plus ces corps sont "carbones plus ils possedent ce pouvoir."

The carbon compounds, it is true, have a mixed effect; they do most certainly interfere with the oxygenation of the blood. Though the blood after death in animals, by being kept in the nitrous oxide, presents a dark colour, its condition is very different from that of death from chloroform and the carbon compounds, as when exposed to the atmosphere it becomes florid, and there is no disintegration of the globules.

On the same principle, pure carbonic acid destroys life by paralysing the heart's action, by dark blood coming into contact with the left ventricle. (Vide experiments by Flourens and Ozanam.) There are certain conditions essential to stimulate the organs of the animal economy. Though light is the natural stimulus of the optic nerves, too much has been known to produce blindness.

Dr. Ozanam also says, " If animal magnetism was a regular science "accessible to every one, without doubt it furnishes to the surgical "profession the most complete realization of an anaesthetic state. We "can put a person to sleep and leave him in that state for hours or "even days without his suffering and without danger to him. All the "functions of life are carried on as in the normal state, nothing is "interfered with but the loss of sensibility."

Dr. Ozanam, you have expressed a great truth with an independence worthy of your distinguished position as a philosopher. It was the conviction of this truth which caused the author to investigate the subject during the years 1839 to 1844. (Vide Report of Boston Committee, Appendix.)

The question must be independently put: What is the state of unconsciousness induced by animal magnetism, or by whatever name it may be called? The time is past to deny that such a condition exists. It is, just as Dr. Ozanam says, the uncertainty of the application which renders it of comparatively little value practically as an anaesthetic.

It was in the year 1842 that the author nearly sacrificed the life of his brother when submitting him to experiments with Indian hemp and alcoholic vapours. Had a fatal result followed, no one, even now, will say that the author would not have been submitted to a criminal trial for murder.

Had the following cases occurred amongst the first who inhaled chloroform, what would have been the result?

In the instance of Miss Stokes, the operator says, She was struck down as if by a flash of lightning. So it was with Walter Badger, Charles Desnoyers, Jean Morgan, Caroline Bates, and hundreds of other cases. Most of these were in the prime of life, with no other ailment than a decayed tooth. Dr. Sansom gives cases where from fifteen to thirty drops of chloroform have produced immediate death, whilst in others 10 1/2 drachms have been inhaled, then suddenly a deep narcotism was induced, followed by death.

In a case of tetanus at Guy's Hospital more than a pint of chloroform was administered in twenty-four hours.

So long as the nervous system is not paralysed there is no danger. Once prostrate it to a negative state, and the chances are indeed small. A single drop of hydrocyanic acid taken by a near relative caused her to fall dead, as if she had been crushed by the force of the most powerful steam hammer. The whole of the nervous system was negatived at once. The nerve molecules were changed instantaneously, and could not recover their normal state.

This allotropic condition is familiar to chemical science; a single particle of sulphur will change entirely the nature of caoutchouc, an infinitesimal particle of arsenic will alter the character of gold. In fine, every metallurgist knows how small a particle of a foreign body will alter entirely the nature of the metal. Apply these principles to the vital economy, and we explain many apparent mysteries.