A tube may be constructed for the purpose of being inserted through the mouth into the _rima glottidis_; if the patient be sensible, the introduction of such a tube might be difficult; but as the patient is in a state of insensibility, the introduction may usually be effected without much difficulty, but not altogether without trouble; for the mere circumstance of having to open the mouth, to pull forward the epiglottis, to direct the tube into the proper aperture, may occasion delay which will be of importance in cases where success depends upon the skill with which the time has been economised. It is for such reasons more expedient to inflate the lungs by means of a tube inserted into one nostril, keeping the other and the mouth carefully closed: the bellows having been thus disposed, the air should be driven into the lungs with a certain degree of force; the lungs will thus become fully inflated, and in the intervals between the different inflations, the air from the lungs will escape by the mouth and by the other nostril, and when the lungs are thus emptied, the process may be repeated. There is but one objection to this method of exciting artificial respiration, viz. that at each inflation, a portion of air will sometimes find its way into the stomach, through the œsophagus: it is very desirable to prevent such an occurrence, for when the stomach is much distended with air, the descent of the diaphragm is prevented, and, consequently, a perfect inspiration cannot be accomplished. The passage of air into the stomach may be prevented by pressing on the thyroid cartilage, so as to close the communication between the pharynx and œsophagus. All that is necessary for the operator is, to produce the inspiration; we are recommended indeed to press the margin of the ribs gently upwards, so as to expel the air, and produce expiration; but this is altogether unnecessary, for the elasticity of the ribs, and the pressure of the abdominal muscles and viscera, and the elasticity of the lungs themselves, are quite sufficient to occasion the expiration without any assistance from external pressure. We must not omit to state that the inhalation of oxygen gas, instead of common air, has been strongly recommended, not only as being in itself a more powerful stimulus, but as being more efficient in the removal of the accumulation of that carbonized matter which, under ordinary circumstances of respiration, is regularly thrown off; the practical eligibility however, of such a plan is very questionable, and to say nothing of the difficulty of obtaining oxygen upon an occasion where the least delay is fatal, it is very doubtful whether the effects of this gas are really such as our theory would at once lead us to believe. We have deemed it necessary to enter into these details, in order to afford some practical instruction upon a subject of manipulation but little understood, but which is undoubtedly the most valuable of all the resources which art