28 



Dr. G. O. Rees on a Function of the 



The second of these expressions becomes identical with the 

 first, when for r its value is substituted, and terms of the second 

 order neglected. Substituting in (2.) it becomes 



dV 4 



V+2«(l +«y) ^ = - -™ 2 (1 +2«j/). 



But 



dV 4fKa Stt du 



7F = --3- + -3 a "^d7-'> 



consequently the preceding expression becomes 



which is the theorem announced by Laplace. 



This theorem may be easily verified with the aid of that 

 demonstrated by Poisson in the Theorie de la Chaleur, pp. 213- 

 221*. 



IV. On a Function of the Red Corpuscles of the Blood, and on 

 the Process of Arterialization. By G. Owen Rees, M.D., 

 F.R.S.f 



ALTHOUGH it has been long known that the contact of 

 oxygen is necessary in order to bring about the change 

 from venous to arterial blood, we are not yet in possession of 

 evidence calculated to explain satisfactorily the manner in 

 which that change is effected. 



The experiments of Dr. Stevens, published some years ago, 

 proved that another cause than oxygenation was sufficient for 

 the production of a bright arterial tint in venous blood ; and 

 it is now universally admitted, in accordance with those expe- 

 riments, that neutral salts possess that power even when the 

 contact of air is carefully avoided. 



Notwithstanding the similarity of effect which they were 

 capable of producing, it appeared doubtful that any connexion 

 would ever be traced between these two causes apparently of 

 so opposite a character. 



The absorption of oxygen was known as necessary to the 

 preservation of animal life ; and it seemed, therefore, that 

 neutral salts ought more properly to be regarded as merely 

 simulating by their action an effect indispensable to existence, 

 rather than as indicating a function necessary to its main- 

 tenance. 



* See Pratt's Mechanical Philosophy, pp. 166-171. 

 •f Communicated by the Author, having been read before the Royal So- 

 ciety, June 3, 1847. 



<^A \ 



