POISONOUS EFFECTS OF CARBONIC OXIDE. 419 
close of the last century ; and in 1802, Clement and Desormes, 
at the instance of Guyton Morveau, undertook a careful exa¬ 
mination of its properties. They not only proved its chemical 
nature, but they also ascertained that it was a poisonous gas. 
Birds put into it dropped dead before they could be taken 
out; and when the experimenters themselves attempted to 
breathe it, they were attacked with giddiness and faintness. 
This experiment was repeated by Sir Humphrey Davy in 
1810, who says that when he took three inspirations of it, 
mixed with about one fourth of common air, the effect was a 
temporary loss of sensation, which was succeeded by giddi¬ 
ness, sickness, acute pains in different parts of the body, and 
extreme debility; some days elapsed before he entirely reco¬ 
vered. It is, he says, fatal to animal life. 
About the same time, the researches of Nysten demon¬ 
strated that the gas was capable of producing great disturb¬ 
ance of the system when injected into the veins; and although 
he concluded that the effects were of a mechanical nature, 
yet the accounts which he has given prove that the gas is a 
dangerous poison. 
Later still, in 1814, the two assistants of Mr. Higgins, of 
Dublin, made experiments with it upon themselves, and in 
one case, that of Mr. Wilter, with almost a fatal result. 
Having exhausted the lungs of air, he inhaled the pure gas 
three or four times, and was suddenly deprived of sense and 
volition; he fell upon the floor, and continued in a state of per¬ 
fect insensibility, resembling apoplexy, and with a pulse nearly 
extinct. Various restorative means were employed, but with¬ 
out success, until they resorted to the use of oxygen, which 
was forced into his lungs, and then his life was restored; but 
he was affected with convulsive agitation of the body for the 
rest of the day. He suffered also from violent headache, 
stupor, and a cpiick, irregular pulse. Even after mental 
recovery he suffered from giddiness, blindness, nausea, alter¬ 
nate heats and chills, and irresistible sleep. The other gentle¬ 
man, after inhaling the gas two or three times, was seized 
with giddiness, tremor, and incipient insensibility. These 
effects were followed by languor, weakness, and headache of 
some hours’ duration. 
Since those experiments were made, others of a more ex¬ 
tended character were instituted by Tourdes and by Leblanc. 
Tourdes found that rabbits were killed in seven minutes when 
they were put into a mixture of one part of the gas with 
seven of atmospheric air. A fifteenth part of the gas in com¬ 
mon air killed them in twentv-three minutes. Leblanc’s ex- 
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periments were made in conjunction with Dumas, and he ascer- 
