PHYSIOLOGY OF ORGANIC LIFE. 127 



medium of open orifices which are greedy to 

 receive it, but through the solid and impene- 

 trable sides of the vessels themselves. A con- 

 struction of vessels which would permit the 

 access of air through, would evidently admit 

 the egress of it also. The assertion has been 

 disproved by experiments which were made to 

 support this opinion. The jugular vein of rab- 

 bits has been exposed, and oxygen air by 

 means of a blowpipe, has been directed upon 

 it, without producing any sensible alteration 

 on the blood that flow r ed through it; on re- 

 moving, however, the external coat of the ves- 

 sel, it was supposed that the color of the blood 

 then underwent some change, and became 

 more florid than before: a false fact such as 

 this, will not, I trust, give any weight to such 

 an opinion, more especially when we reflect 

 that the actual and palpable existence of air in 

 the blood, is immediately attended with con- 

 vulsions, and with death. It is the mode which 

 many farriers now adopt to kill horses. By 

 means of a blowpipe they introduce a small 

 quantity of air into the jugular vein, which, after 

 a few struggles, puts an end to the animal's 

 existence. 



Although chemical physiologists have been 

 undecided with respect to the quality of the 

 matter which has been received from the lungs 

 into the blood, they have been, generally speak- 



