ANAESTHETIC AGENTS. 
309 
sensible, and this insensibility lasts for upwards of five 
minutes. When the heat returns, and the blood again cir- 
culates through the part, there is increased redness, but this 
is so far from indicating reaction or an inflammatory con- 
dition, that wounds of the skin so congealed have invariably 
healed by the first intention more speedily than under 
ordinary circumstances. The small arteries have, in fact, 
lost their tonicity for a time, and are thus rendered incapable 
of the inflammatory process.” 
He adds: “The principal objection that has been made to 
congelation, both as a remedy of disease and as an anaesthetic, 
is founded on the most erroneous idea, that it endangers the 
vitality of the part subjected to it. This unfortunate error 
arose from not reflecting on the essential difference that 
exists between a part congealed for a few minutes only, while 
the general circulation of the blood continues vigorous, and 
a part congealed for hours, with the circulation in a feeble 
condition, as happens in exposure to the cold of northern 
climates or severe winters. It is enough, in refutation of 
this idea, to state that when attempting it for the formation 
of an issue, I have never succeeded in destroying the vitality 
of the skin by a very long-continued congelation ; nor have 
I ever heard of any untoward event having followed con- 
gelation in the practice of others using the remedy in the 
usual way.” 
Dr. Dauniol, of Toulouse, recommends the fumes of hen- 
bane, belladonna, and other narcotics of this class, to be 
inhaled rather than chloroform or ether and the allied bodies. 
The modus operandi of these agents seems to be as yet an 
undecided question. There being a resemblance in their 
action to the effects produced by intoxicating liquors, and 
the substances being similar in composition, some have been 
inclined to view them as identical; more especially, since it 
has been the case that amputation of limbs and other opera- 
tions have been performed on persons in a state of drunken- 
ness, and they have been altogether unconscious of it. 
Chemists have thought that the inhaled carbon becomes 
converted into carbonic acid, which produces its sedative 
action on the nerves, while the hydrogen is changed into 
water; both at the expense of the inspired oxygen. Dr. 
Snow disputes this, averring that both ether and chloroform 
are given off in an unchanged state by exhalation, and are 
detectable in the urine, and also in an amputated limb or a 
dead body. Somewhat confirmative of this is the fact that 
Mr. Varnell, assistant-professor at the Royal Veterinary 
College, destroyed a horse while under the influence of 
