UNDER CHLOROFORM. 
23 
we employ under two general heads, of Gases and Volatile 
Fluids, and I will set the most reliable substances in this order, 
adding to the name of each substance its chemical composition 
and physical characteristics. 
Table I.- 
-GASES. 
Name. 
Chem. Comp. 
Density H=l. 
Nitrous oxide 4 • . 
. n 2 o 
22 
Methylic ether . . 
. c 2 fi 6 o 
23 
Chloride of Methyl . . 
. CH 3 C1 
25-25 
Table II.— VOLATILE FLUIDS. 
Vapour Density 
Name. 
Chem. Comp. 
Boiling Point. J± = l. 
Ethylic ether .... 
. c 4 h 10 o 
92° F. 37 
Bichloride of ethylene (Dutch liquid) 
. c 2 H 4 ci 2 
175° F. 49-5 
Bichloride of methylene 
. CH 2 C1 2 
104° F. 42-5 
Terchloride of formyl (chloroform) 
. CHC1 S 
142° F. 59-75 
Tetrachloride of carbon 
. CC1 4 
172° F. 77 
I might expand these tables very largely. To the gases I 
might add carburetted hydrogen, light and heavy ; carbonic 
acid, carbonic oxide, and hydrogen gas. To the liquids I might 
add methylic alcohol, chloride of ethyl, hydride of amyl, 
amylene, and many others, not omitting turpentine, which, at a 
push, has actually been administered successfully to the human 
subject. It is better to take simple types of those agents which 
are most direct in action, or most in use at this hour. Respect- 
ing those agents noted in our tables, it may be well to say of 
them at once, that, although they are the best up to the present 
time discovered, not one of them is to be considered perfect. 
All the gases are faulty because, being gases, they are practically 
unmanageable for ordinary application. Nitrous oxide gas, 
moreover, although it produces insensibility, causes, at the same 
time, darkening of the arterial blood, painfully rapid breathing, 
a countenance terrible to behold, and imminent approach to 
death. The liquids, on their side, are practical for administra- 
tion, but more or less faulty in action. 
At a future day, keeping to the same text, I will endeavour to 
point out the relative advantages and disadvantages of each of 
these agents in detail ; and will try to explain what is wanted 
in an anaesthetic agent to make it in all respects perfect ; 
and when I say perfect, I mean so perfect, that the removal of 
sensibility, and thereby the prevention of suffering by it, shall 
be attended with no anxiety, and with no sign or symptom that 
shall excite in the operator and administrator the anxiety which 
every administration, hitherto, has called forth. 
