ANAESTHETICS. 
25 
cleatli is near ; but, even yet, the ganglionic nerves of the sym- 
pathetic system perforin their functions, and the heart and 
intestines continue to move for a time, often with vigour. 
It is thus seen that when anaesthetic vapours are inhaled the 
different nervous centres lose their powers in the inverse order 
to their essenticclness to life ; the functions of the sympathetic 
nerves ceasing last of all, and the heart and womb retaining 
for a time, therefore, then- contractile power during states of 
anaesthesia, so deep as not only to involve the annihilation of 
consciousness and sensibility, but also of respiration. In order 
to render a patient insensible to the most severe surgical opera- 
tions, it is never necessary to proceed further than the third 
stage of anaesthesia ; in child-birth still less is required, and 
the patient may be kept on the borders of consciousness, or be 
conscious even during the whole time. 
Here, then, in a few words, is the explanation of these won- 
derful phenomena. 
In the human body exist, as I stated before, different 
systems of nerves, and the art of producing anaesthesia consists 
in allowing one system to work as usual whilst the other 
systems are under the influence of sleep. The nerves of motion 
and of sensibility are made to sleep, whilst the nerves of 
organic life continue their functions. We are now enabled to 
appreciate these wonderful discoveries, and to admire the mar- 
vellous arrangement of the nervous system. The problem of 
depriving man of sensibility and motion, without impeding 
respiration, circulation, digestion, or, in other terms, of 
depriving him of his faculty of moving and of feeling pain, 
without depriving him of life, has been solved. During 
anaesthesia,, then, man lives like a plant — his animal faculties 
are taken from him for a time. 
Since the discovery of chloroform, several substances have 
been found to have a similar wonderful action upon the nervous 
system. Among them are two chemical products, called 
j.mylen and Acetone. 
Amylen, a peculiar volatile liquid, obtained from impure 
potato spirit, was first administered by Dr. Snow, at King’s 
College Hospital, London, in November, 1846; and he con- 
tinued to use it until July, 1857. During this period, 238 
persons were operated upon during anaesthesia produced by 
amylen, out of which number only two deaths occurred. It 
was afterwards used in France ; but I do not know that it 
possesses any advantage over chloroform. 
In 1859, Dr. Kidd proposed the use of Acetone (a volatile 
liquid, produced by distilling acetate of lime, and which has 
long been known to chemists) as a powerful anaesthetic. Its 
agreeable odour, which resembled somewhat essence of mint 
