To settle this question Kionka con ducted a series of researches to deter mine quantity of ether or chloroform necessary to produce narcosis. He found the dose required to be relatively small. Narcosis was obtained when the air con tained from 0.15 to 1.3 per cent. of chlo roform, or 2.1 to 7.9 per cent. of ether. The minimum quantity of ether neces sary to produce ancesthesia could be greatly exceeded without endangering life, and narcosis could be prolonged by using the same dose, while, under similar conditions, chloroform invariably caused death of the animal. Sleep under ether, when once established, aould be main tained with a smaller dose than that re quired to produce it. From the begin ning chloroform caused early arrest of heart and respiration.
Robert Bell has noted that the symp toms of approaching danger under chlo roform always appear in the followina order: (a) coughing., (b) gasping, (c) choking, and (c1) struggling. If, at the first appearance of coughing,. the vapor is given more diluted. no further diffi culty will arise. On the other hand. W. A. Parker ascribed the small number of deaths observed in Scotland to the fact that the amesthetists are not afraid of chloroform; they use it fearlessly in un stinted doses, pushing the patient rap idly under.
Buxton states that there seems every reason to believe that an overdose of chloroform may be arrived at in one of two ways: (1) a sudden intake of a lethal dose, which, according to Sansom, who followed Snow's emphatic teaching, may be taken when even a small quantity of the anaesthetic is thrown on lint or a towel, or (2) through accumulation of the drug in the body. This commonly shows itself by paralyzing the medullary centres and so producing cessation of respiration. Impairment of expiration is the most usual cause of this, due in many cases to some mechanical cause, such as emphysema_, falling back of the tongue, sucking in of the lips, or block ing of the air-ways by mucus or blood.
As regards the lower mortality re ported from Scotland, Buxton argues that many deaths under chloroform have occurred in that country; even as early- as in the days of Simpson. As no public investigation is held correspond ing with coroners' inquests, as is the case in England, no report gets into the pub lic press. He reaches a conclusion sus tained by experience, and verified by a wide-spread review of the literature, to the effect that every individual requires a specific dose: the drunkard and athlete require much ; the pale, f rail, analnic woman very little.
The stages of chloroform narcotism as given by Snow and Buxton are divided into four:— The first stage, from the commence ment of inhalation to the loss of con scious control of the limbs.
The second, to the stage of loss of con junctival reflex and rig,idity of the mus cles.
The third, or surgical stage, when the muscles are relaxed (in the main), the corneal reflex is lost, and the pupil is contracted.
The fourth stage, when the medullary centres are affected, the pupils dilate, the respiration gradually fails, the muscles are absolutely relaxed, the sphincters cease to act, while the circulation fails.
Beyond this stage convulsions occur, the breathing ceases, and the heart and circulation come to a stand-still. The complete relaxation of the muscles can, in some cases, be arrived at only.by the patient's entering the fourth stage, and, in the case of chloroform, such pushing of the anaesthetic can only be accom plished by seriously jeoparding the pa tient's life. In the case of ether, how ever, a patient can, with ordinary care, be allowed to pass into this stage with out danger.
At all times during the administration of the ansthetie the respiration and the circulation should be simultaneously watched.
Untoward Effects.—The chances that no trouble will be met with stand as 1500 does to 1, provided average care has been taken in determining whether the case be not one offering unusual chances against a successful administration. But in all cases certain allowances must be made not only for previously-undiscov ered elements which may suddenly bear their influence -upon the issne, but also for k-nown conditions which also modify the form of issue.
Owen states that there is always risk in giving chloroform or any other anms thetic to a child: but this risk- is dimin ished in proportion as the vapor is ad ministered in a careful manner and by a well-instructed person. It is impor tant to bear in mind, in this connection, that the general impression that children very rarely succumb to the influence of chloroform is erroneous. The many deaths in children ranging from early in fancy to 15 years of age have served to emphasize this fact.