126 RESPIRATION. L.ECT. VI. 



therefore, must have been dissolved in the blood, and have 

 been disengaged by hydrogen, by the action which one gas 

 has on another of a different nature, dissolved in a liquid. 

 If we have substituted arterial for venous blood, we should 

 have obtained a smaller quantity of carbonic acid. If we 

 substitute azote for hydrogen, there is also disengaged, by 

 the contact of that gas with the blood, carbonic acid, the 

 quantity of which from venous blood should be more than 

 double that obtained from arterial blood. By this method 

 we not only obtain carbonic ( acid, but also some oxygen 

 and azote, which are disengaged along with it. The re- 

 sults obtained by Magnus are so deserving of confidence 

 and so important, that I think it my duty to make you ac- 

 quainted with his numerical results. He extracted and 

 analyzed the gases dissolved in the blood, by means of a 

 peculiar apparatus, by the aid of which he made a vacuum 

 over the blood itself, and st> collected the gases which 

 were set free. If I were to introduce a certain quantity 

 of blood, at the moment when it is drawn from the animal, 

 into the vacuum of the barometer, you would observe that 

 the column of mercury would fall considerably; and by 

 this means also we might collect the gases of the blood. 

 Here is a table containing the numbers obtained by Mag- 

 nus. 



Table of Gases evolved from the Blood. 



Cubie Centimetres. 



125 parts arterial 1 C 5-4 carbonic acid, 



blood of a horse > 9-8 of gas, compo ed of < 1-9 oxygen, 



yielded . . 3 f 2'5 azote. 



205 parts venous 1 C 8-8 carbonic acid, 



b'ood of a horse > 12-2 of gas, composed of / 2-3 oxygen. 

 yielded . > f M azote. 



130 parts arterial ) I 10-7 carbonic acid, 



blood of a hi.rse ' 16-3 of gas, composed of 1 4-1 oxygen, 

 yielded . . > f 1-5 azote. 



