Bdfi Intelltgetice and Miscellaneous Articles, 



stances, converting them into carbonic acid, and perhaps also into 

 water. The carbonic acid, instead of oxygen, is then absorbed by 

 the blood, and reaches the lungs with it, to be removed by contact 

 with the atmosphere ; a fresh quantity of oxygen is then absorbed 

 instead of it, and undergoes the same changes. 



The quantities of oxygen which were then separable from the 

 blood by the air-piAnp were but small. The author has now en- 

 deavoured to procure larger quantities from it, and has been occu- 

 pied with an examination of the general absorbent properties of the 

 blood, especially with regard to oxygen. With this object, the 

 blood was agitated with continually renewed portions of atmospheric 

 air, and to ascertain subsequently how much air it contained from 

 absorption, it was placed in a vessel filled with mercury, and which 

 was closed with an iron stop-cock. This was then screwed upon a 

 second vessel, likewise closed with a stop-cock, and containing car- 

 bonic acid. On opening the cock, the mercury fell out and the 

 carbonic acid ascended to the blood. The vessels were then sepa- 

 rated, and the blood continually agitated with the carbonic acid. 

 The vessel was then screwed upon another completely filled with 

 mercury, and the gas was allowed to collect in this. Carbonic acid 

 was then in the same manner again mixed with the blood, which 

 was then agitated and the gas also conveyed into this vessel ; and 

 this process was repeated several times. Finally, the collected gas 

 was examined, the carbonic acid being absorbed by caustic potash, 

 the oxygen being detonated with hydrogen, and the remainder con- 

 sidered as nitrogen. {■ <j(.j<i5j, 3<<Tii ^J3W 



Although these experiments appear so simple, ' it was at fitst im- 

 possible to carry them out, because the time which it was requisite 

 to allow for the subsidence of the froth after each agitation was so 

 great that decomposition commenced in the blood before the com- 

 pletion of the experiment. 



This difficulty was subsequently removed by adding a drop of 

 bil, which when placed on the surface of the blood soon caused the 

 disappearance of the froth. -. 



Numerous and repeated experiments, made in this manner, on the 

 blood of calves, cattle and horses, have yielded tolerably uniform 

 results, the minimum of oxygen being 10 per cent, and the maximum 

 12'5 per cent, of the volume of the blood, and the minimum of ni- 

 trogen being 1'7 per cent, and the maximum 3*3 per cent, reduced 

 to the temperature of 32° F. and the mean barometric pressure. 

 ■ The proportion in which the oxygen and nitrogen found in the 

 ^as obtained from the blood are, affords another indirect proof that 

 no air had entered the vessels from without during the experiment. 

 Had this been the case, the quantities of the two gases found 

 would have been more nearly in the proportions existing in the at- 

 mosphere, whilst the oxygen ordinarily amounted to 3 and frequently 

 4 and 5 times as much as the nitrogen. 



' Although the difference between 10 and 12'5 per cent, is not in- 

 considerable, still it might appear remarkable that the experiments 

 iigree bq well with one another, especially as they do not liberate the 



