740 CHEMISTR Y OF RESPIRA TION. 



Speck 1 found, when he breathed a mixture of gases containing 11 '51 

 per cent, of carbon dioxide, that 528 c.c. carbon dioxide were absorbed by 

 the blood in a minute, whereas under normal conditions 230 c.c. of that 

 gas would have been discharged. "In a dog Pfliiger 2 found that there 

 were, under normal conditions, 29'8 volumes per cent, carbon dioxide 8 

 in the arterial blood, but 56*8 volumes per cent, after the dog had 

 breathed for one minute a mixture containing 70 per cent, oxygen 

 and 30 per cent, carbon dioxide. Zuntz 4 observed an increase to 

 8 9 '6 volumes per cent, carbon dioxide when a dog breathed for one 

 minute and a half a mixture containing 36*9 per cent, carbon dioxide. 



Numerous experiments were made by Paul Bert 5 upon the action of 

 this gas upon different forms of life. He found that a percentage of 13 '5 

 to 17 was fatal for reptiles, 24 to 28*for sparrows, and 30 or more for 

 mammals. When the air contained 30 to 40 per cent, of carbon dioxide, 

 death resulted owing to the high tension of the gas in the blood ; thus in 

 some dogs the percentage of carbon dioxide in the arterial blood was 

 116, in the venous blood 120. Complete insensibility could be produced 

 long before any danger to life arose, and thus the gas mixed with air 

 or oxygen could be used for the production of anaesthesia. 6 



Carbon monoxide. The physiological action of this gas is of the 

 utmost practical importance, since it is every year the cause of 

 numerous deaths in cases of poisoning from coal gas, the fumes of kilns 

 and coke fires, and in the air of coal mines, especially after explosions. 

 Although it has long been known that carbon monoxide is poisonous, 

 it was about the year 1857 that Claude Bernard 7 and Hoppe-Seyler 8 

 first pointed out that the carbon monoxide displaced the oxygen of 

 the blood by forming a more stable compound with haemoglobin, and 

 thus brought about asphyxia. 9 The action of this gas has been studied 

 by many observers. 10 



The most recent investigations are those of Haldane, 11 who has 

 experimented both upon himself and upon mice. The following are his 

 chief conclusions : The symptoms produced in man do not become 

 sensible until sufficient carbonic oxide has been absorbed for the 

 corpuscles to become about a third saturated ; with half saturation of 

 the corpuscles the symptoms become urgent. The symptoms are due 

 solely to deficiency in the percentage of oxygen in the blood, and are 

 similar to those experienced by mountaineers and balloonists at high 

 altitudes. The time required for the symptoms to appear in different 

 animals is proportional to the respiratory exchange per unit of body weight, 

 and is about twenty times as long in a man as in a mouse. Hence 

 it is possible with safety to use a mouse as an indicator of the presence 

 of poisonous proportions of carbonic oxide in the atmosphere of a coal- 



1 CentralU.f. d. med. Wissensch., Berlin, 1876, No. 17. 



2 Arch.f. d. ges. PhysioL, Bonn, 1868, Bd. i. S. 103. 



3 Measured at and 1 m. 



* Arch.f. d. ges. PhysioL, Bonn, 1888, Bd. xlii. S. 408. 



5 "La pression barometrique, " Paris, 1878, p. 982. This article, pp. 743-45. 



6 See also Gre"hant, Compt. rend. Soc. de Uol., Paris, 1887, p. 542. 



7 "Le9ons sur les effets des substances toxiques et me'dicamenteuses," Paris, 1857, p. 

 184 ; " Lecons sur les liquides de Porganisme, " Paris, 1859, tome i. p. 365 ; tome ii. p. 427. 



8 Virchows Archiv, Bd. xi. S. 228 ; Bd. xiii. S. 104. 



9 This Text-book, article "Haemoglobin." 



10 Gaglio, Arch. f. exper. Path. u. PharmakoL, Leipzig, 1887, Bd. xxii. S. 233 ; Gruber, 

 Arch.f. Hyg., Munchen u. Leipzig, 1883, Bd. i. S. 145; Welitschkowsky, ibid., S. 210; 

 Fokker, ibid., S. 503 ; Gre"hant, "Les poisons de 1'air," Paris, 1890. 



11 Journ. PhysioL, Cambridge and London, 1895, vol. xviii. p. 430. 



