AIR VITIATED BY BREATHING. 
74i 
mine. Distinct symptoms are produced by air containing *05 per cent. 
of the gas, and urgent symptoms with - 2 per cent. The poisonous 
action diminishes as the tension of oxygen increases, and vice uersd. At a 
tension of two atmospheres of oxygen this poisonous action is abolished 
in the case of mice,-and this disappearance of the poisonous action is 
due to the fad that at high tensions of oxygen the animals can dispense 
entirely with the oxygen-carrying function of haemoglobin, and can 
obtain enough oxygen from the gas dissolved in the plasma of the 
blood. 
As regards the gases of the blood, after poisoning with carbon 
monoxide, I rrehant ' found that 100 c.c. of blood from the carotid of a 
poisoned dog contained 6 c.c. of oxygen, 30 - 3 c.c. of carbon dioxide, and 
20 c.c. of carbon monoxide ; whereas a sample of blood taken before the 
administration of the gas yielded 195 c.c. of oxygen and 44-2 c.c. of 
carbon dioxide. The following figures show the effect of different doses 
of carbon monoxide upon the gases of the blood of clogs poisoned by the 
eas:— 
CO i.N Ixspired Air. 
Ga-es of Blood. 
CO.. 
2 . 
X. 
CO. 
1 in 1000 . 
1 ,, 20<i0 . 
1 ,, 3000 . 
1 „ 4000 . 
2S-9p. ct. 
51-8 ,, 
42-2 ,, 
40-4 „ 
12-2 p. ct. 
15 '5 ,, 
13-4 „ 
21-5 „ 
1*5 p. ct. 
1-5 „ 
1-8 „ 
1-5 „ 
5 "5 p. ct. 
2-8 „ 
1-7 :, 
1-3 „ 
The administration of small doses of carbon monoxide, enough to 
produce unconsciousness, causes a marked reduction in the respiratory 
exchange 2 of a mouse, and its temperature falls. 
According to Gaglio, 3 carbon monoxide present in the blood is not 
oxidised, but St. Martin 4 states that it is slowly oxidised in the 
presence of oxyhemoglobin. The compound of this gas with haemo- 
globin is partly dissociated in sunlight, but upon these points more 
details will be given in the discussion upon the gases of the blood. 
The respiration of air vitiated by breathing. — The air vitiated 
by respiration, as in overcrowded rooms, is distinctly unwholesome, but 
the causes of this deleterious action are not simple, but may arise from 
substances given off either from the lungs by respiration, from the body 
by perspiration, or from the injurious products of disease or tilth. 
Even as early as 1674. Mayow 6 had stated that an animal died if 
kept in a limited quantity of air. because it had used up the respirable 
portion, the nitro-aerial gas (oxygen); he further pointed out that re- 
spiration and combustion produced similar changes in the air. About 
the year 1726, Stephen Hales 7 observed by experiments upon himself 
1 Compt. rend. Soc. de biol., Paris, 1892, p. 163. 
2 Haldane, Journ. Physiol., Cambridge and London, 1895, vol. xviii. p. 
3 Arch. f. exper. Path. a. Pharmakol., Leipzig, 1887, Bd. xxii. S. 233. 
4 Compt. rind. Acad. d. sc, Paris, 1891, tome cxii. p. 1232. 
5 Haldane, loc. cit. 
6 " Tractatus quinque," Oxonii, 1674. 
7 "Statical Essays," 2nd edition, vol. i. p. 236 ct seq. 
430. 
