Intelligence and Miscellaneous Articles, 301 



Carbonic acid gas 4*29 vols. 



Oxygen , 1*12 „ 



Azote '54 „ 



Total 5-95 vols. 



ITie arterial blood of the calf contains more, and the venous blood 

 less oxygen, than that of the horse. 



M. Magnus observes that these experiments, and others which 

 we have not copied, appear to show that the gases contained in the 

 blood of the animals, amount to about one-eighth or one-tenth of 

 the quantity employed. He admits however that the experiments 

 are not absolutely precise, because they were not all continued the 

 same length of time, &c. But he observes, that as the proportions 

 between the oxygen and carbonic acid are invariably the same, these 

 results may be regarded as satisfactory. 



With regard to the theory of respiration all experimentalists agree 

 as to the reciprocal proportions between the carbonic acid expired 

 and of the oxygen absorbed ; while however some of them are of 

 opinion that those quantities are always equal, as must happen if the 

 oxygen gas were employed merely in the formation of carbonic acid 

 in the lungs, there are chemists whose results show that more oxy- 

 gen is inspired than carbonic acid expired. Messrs. Allen and Pepys 

 observed that this was constantly the case when the same air was 

 repeatedly respired. 



M. Magnus adds, that this fact, so inexplicable by other theories, 

 is an immediate consequence of the hypothesis founded on the law, 

 that a liquid holding a gas in solution parts with it when it comes 

 in contact with another gas. 



Another circumstance noticed by Messrs. Allen and Pepys is as in- 

 explicable as the preceding, namely, that by the respiration of oxy- 

 gen, or by a mixture of oxygen and hydrogen, azotic gas is constantly 

 expired, the volume of which is proportional to the bulk of the ani- 

 mal ; this proves that it cannot at all be attributed to the air. 



It now remains to be shown that the carbonic acid extracted from 

 the blood is in sufficient quantity to account for the whole of that 

 which the lungs expire. The results obtained on this subject are 

 discordant ; those of Messrs. Allen aud Pepys evidently exceed what 

 they should be ; for Berzelius has shown that, if correct, it would 

 require six pounds and a quarter of solid nourishment in 24 hours 

 to produce the quantity of carbon consumed. 



Taking then the results obtained by Davy as a mean of those of 

 Lavoisier, Allen and Pepys, although perhaps a little too high, we 

 shall have 13 cubic inches as the quantity of carbonic acid gas ex- 

 pired by a man. If it be further admitted, that at each pulsation 

 of the heart an ounce of blood arrives at the lungs 75 pulsations in 

 a minute would convey live pounds of blood in the same time. This 

 is the minimum quantity which can be admitted ; for it is very pro- 

 bable that five pounds of blood pass through these organs every mi- 

 nute : these five pounds produce 13 cubic inches. It has been already 

 mentioned that the blood contains at least one-fifth of its volume of 

 carbonic acid; and as a pound is equal to 25 cubic inches, each 

 pound of blood would contain at least 5 cubic inches of carbonic 



