METHODS OF ANALYSIS. 217 



Scherer* has in many respects improved the analysis of the 

 blood^ and his method is the most correct that has yet been 

 suggested, although it presents the same prominent deficiency as 

 the others, namely, the mere determination of those constituents 

 of the blood-corpuscles which are coagulable and insoluble in water, 

 together with the uncertainty attaching to the absolute value in 

 consequence of the impossibility of estimating the serum that is 

 actually enclosed. Thus, Scherer does not compare the solid residues 

 of the serum and of -the defibrinated blood, but the quantities of the 

 coagulable constituents of both fluids, in order to find the number 

 of dry blood-corpuscles, and calculates the salts, fats, and extractive 

 matters independently. From the comparative investigations of 

 Hinterberger, it appears that Scherer's method yields the smallest 

 number for the blood-corpuscles, and the reason of this is easily 

 seen ; for the dry corpuscles, in Scherer's analyses, are deprived 

 not only of all their soluble constituents, but also of an undeter- 

 mined quantity of earthy phosphates, by the acetic acid employed 

 in the coagulation, and in addition to this, a little pigment some- 

 times remains in solution in the fluid, notwithstanding the boiling 

 and neutralisation, and there is then so much lost in the calculation 

 of the blood-corpuscles. The principal reason may, after all, lie, as 

 v. Gorup-Besanez and Hinterberger have suggested, in the manner 

 in which Scherer obtains the defibrinated blood, which is as follows : 

 he applies pressure to the clot, and mixes the fluid which escapes 

 with the serum a method of procedure by which a greater or 

 lesser number of corpuscles, or at all events of their remains, must 

 invariably be retained in the fibrin, and thus be lost in the deter- 

 mination of the mass of the dry blood-cells. 



We now arrive at a method which appears to avoid the errors 

 of those we have previously described, and to separate the whole 

 of the serum from the corpuscles. It is based on the property 

 (mentioned in p. 183) which a solution of Glauber's salts possesses 

 of rendering the blood-corpuscles capable of being retained on a 

 filter. It was first applied by Figuier, and subsequently improved 

 by Dumas, and more recently by Hoflef. Defibrinated blood is 

 treated with eight times its volume of a concentrated solution of 

 Glauber's salts and filtered, the residue on the filter is rinsed 

 with the same solution (Dumas simultaneously conducts a stream of 

 oxygen through the mass lying on the filter), and finally the mass 

 of blood-cells retained on the filter is either directly coagulated 



* Otto's Beitrag z. d. Analysen gesunden Bluts. Wurzburg, 1848. 

 t Chemie u. Mikrosk. am Krankenbette. S. 132. 



