QUANTITATIVE ANALYSIS. 131 



their weight in their natural moist condition, gives us no idea 

 of their real proportion. So apparent has this been to phy- 

 siological chemists, that attempts have been made by Denis, 

 Schmidt, Vierordt, Figuier, and others to estimate the moist 

 corpuscles; but in attempting to attain extreme accuracy, 

 these observers have almost entirely failed, and their ideas of 

 the real proportion of the corpuscles are merely conjectural. 

 These remarks only apply to researches into the organic 

 constituents of the blood. The analyses with reference to the 

 inorganic elements, though they have not yet shown us the 

 exact proportion of each one of them, are of course accurate 

 as far as they go. 



The various processes for analysis of the blood now em- 

 ployed by chemists do not differ very much. As one of the 

 best, we may take that recommended by Becquerel and Rp- 

 dier, who are perhaps as high authority on this subject as 

 any. Their process, which we give in its essential particulars, 

 has an advantage over most others in simplicity. 



Two specimens of blood are taken and carefully weighed ; 

 one of them is defibrinated, the fibrin collected, dried, and 

 weighed, which gives the proportion of fibrin. The other 

 is set aside to coagulate. A known weight of the defibrinated 

 blood is then evaporated to dryness, and the proportion of 

 dry residue carefully estimated. The residue is then calci- 

 nated to give the proportions of inorganic constituents, which 

 remain after the organic matters have become volatilized. 

 After the blood set aside to coagulate has separated into clot 

 and serum, a definite quantity of the serum is evaporated to 

 dryness and the residue estimated. As the dry residue of the 

 defibrinated blood contains the solid matters of the serum + 

 the dried corpuscles the proportion per 1,000 parts of the* 

 solid matters of the defibrinated blood the proportion per 

 1,000 parts of the solid matters of the serum, would give the 

 proportion of corpuscles. 



We thus have obtained the proportions of water, of inor- 

 ganic matter, of corpuscles, and of fibrin. The next step is 



