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XIV. An Account of some Experiments on the Blood in connexion ivith the Theory of 

 Respiration. By John Davy, M.D. F.R.S., Assistant Inspector of Army Hospitals. 



Received May 31, 1838.— Read June 21, 1838. 



Connected with the theory of respiration and of animal heat there are many 

 questions of interest respecting the blood, about which physiologists differ in opinion, 

 and which consequently are fit subjects for further inquiry. 



Some of the more important and fundamental of these questions I have endeavoured 

 to investigate experimentally, and in the present communication I propose to submit 

 to the Royal Society the results which I have obtained, with the hope that they may 

 be considered not unworthy of a place in the Philosophical Transactions. 



I. Is blood capable of absorbing o.vygen independent of putrefaction ? 



To endeavour to satisfy myself on this point, on which in a former inquiry I had 

 arrived at a negative conclusion in opposition to the commonly received opinion, I 

 have employed two methods of experimenting: one, of agitating blood, recently drawn 

 and rapidly cooled in common air and in oxygen, in a tube of the capacity of two 

 cubic inches, divided into a hundred parts ; the other, of agitating it in larger quan- 

 tities with the same airs, in the very convenient apparatus employed by Dr. Chris- 

 TisoN when engaged in a similar inquiry, consisting of a double tubulated bottle of 

 the capacity of thirty-two cubic inches, provided with stop-cocks adapted by grinding, 

 to one of which a moveable bent glass tube was fitted to connect it with a pneumatic 

 trough, and to the other a perpendicular tube surmounted by a funnel. 



The blood subjected to experiment in every instance was prepared by the displace- 

 ment of its fibrin. This was done by agitating it with small pieces of sheet-lead in a 

 bottle filled to overflowing and closed with a cork, enveloped in moist bladder and 

 covered over viith the same, tied round the neck of the bottle, so as to exclude atmo- 

 spheric air, whilst in the act of coagulating and of cooling, and to allow, when cooled, 

 of the withdrawal of the cork. 



Prepared thus, and rapidly cooled, I have tried different specimens of blood, venous 

 and arterial, of Man, of the Sheep, Ox, Dog and Cat ; and the results, when the blood 

 has been taken from a healthy animal, have been decisive and consistent. In every 

 instance, whether atmospheric air or oxygen was used, after agitation, there was a 

 marked diminution of the volume of air. 



In the examples which it may be advisable to bring forward, I shall confine myself 

 to a few of the experiments I have made on the blood of the Sheep. 



Using the graduated tube over mercuiy, sixty-two measures of arterial blood from 



2 o2 



