ANESTHETICS. 
27 
from the earth, and from its weight, much greater than that of 
air, forms a thick stratum of suffocating gas upon the floor of 
the cavern. When a man enters, his head and shoulders rise 
above the stratum of gas, and he breathes pure air ; but when 
a dog is introduced, his head and body plunge completely into 
the carbonic acid gas, and he soon falls down, suffocated. The 
animal is then removed by the guide, laid upon the grass out- 
side, and, in a short time, recovers. 
Dr. Ozanam has shown that this suffocation by carbonic acid, 
when produced properly, affects a patient like chloroform, 
ether, or nitrous oxide, and can be made available in surgical 
operations. Indeed, he considers that carbonic acid has certain 
advantages over chloroform, and that it is less dangerous than 
the latter. 
But of all the means hitherto employed to render man per- 
fectly insensible to pain, the most curious, perhaps, is that 
called Hypnotism or Braidism, discovered many years ago by 
the late Dr. Braid, of Manchester, and practised successfully 
by him in England. It consists in placing some object, such as a 
cork or a piece of polished metal, at a short distance from the 
forehead of the patient, and requesting him to fix his eyes 
steadfastly upon it. After some time, which varies from a few 
minutes to half an hour or so, according to the constitution of 
the individual, the patient’s eyes seem riveted upon the object 
in question, and for some moments he remains thus, without 
once closing them; they then suddenly close, and the patient 
falls into what is termed the hypnotic state, a kind of somnam- 
bulism similar to mesmerism. Consciousness has disappeared, 
and complete insensibility to pain has ensued. 
Braid’s discovery seems to have been abandoned for some 
time past by the medical world, but was occasionally put in 
practice by lecturers on the so-called “ electro-biology,” &c. 
Lately, however, it has been taken up again in Paris, by M. 
Paul Broca, surgeon to one of the hospitals of that city ; and 
Dr. Braid just lived long enough to hear of his method of 
producing anaesthesia meeting with singular success in the 
hands of M. Broca. One of the first results obtained by the 
latter was made known a year or so ago at the Academie do 
Medecme. It was the case of a woman who had repeatedly 
refused to be operated upon for a large turn our. At length, 
M. Broca induced anaesthesia by causing the patient to fix hex- 
eyes upon a metallic disc which he held above her forehead. 
In about a quarter of an hour, a state of complete insensibility 
supervened, and the operation was performed. On returning 
to her senses, the poor woman would not believe that the 
operation had indeed taken place whilst she was under the 
influence of sleep. 
