15 
ANAESTHETICS. 
BY T. L. PHIPSON, M.B., PH.D., F.C.S. 
B Y anaesthetics are understood certain substances which 
have the property of inducing a peculiar state of the 
nervous system called anaesthesia, and thereby rendering 
us insensible to pain. They rank among the most powerful, 
and, at the same time, most useful agents that man has hitherto 
obtained from the hidden treasures of nature. From the 
moment of his birth (and perhaps even some time before birth), 
man is liable to experience what is called pain. The human 
body is so organized that, in a state of perfect health, we feel 
nothing ; and there are some persons, though few indeed, who 
pass through life almost without knowing what pain is, whilst 
others again are almost constantly in a state of suffering. 
When pain is felt in any part of the body, that part is not in 
its normal condition, it is no longer in the state of insensibility 
which characterizes perfect health. 
But pain is not without its uses : it warns us from danger, 
and without its existence our own existence would infallibly 
cease. For instance, if no pain were felt when the hand or foot 
is placed in the fire, we should not be tempted to withdraw it 
unless we happened to see it consuming. Some time ago a 
labourer lost liis leg by sleeping too near a lime-kiln ; he felt 
nothing till he awoke, when it was too late. Likewise, if no 
pain were felt when boiling water, or some powerfully acrid 
substance, is poured down the throat, we should not be 
tempted to desist from introducing it into the body, and 
so our life would, sooner or later, be inevitably destroyed. In 
lower animals, where the organs of sensation cannot be detected 
so distinctly as in man, and in some where such organs seem 
indeed to be completely wanting, there is still an existing 
faculty equivalent to pain, and followed by similar effects : 
thus, if we touch the tentacles of a sea-anemone, in which 
organs we can find no nerve-fibres, the animal instantly with- 
draws them as if hurt, in the same manner as a dog would 
withdraw his leg if his foot were pricked with a pin. In the 
human body, we have three kinds of nerves : viz., the nerves 
of sensation, the nerves of motion, and the nerves of organic 
life, which govern the functions of digestion, respiration, secre- 
