ITS PHYSICAL, CHEMICAL, AND STRUCTURAL CHARACTERS. 171 



the greater number of results hereafter to be cited have been obtained by the 

 method of MM. Andral and Gavarret, 1 which has been followed, with slight 

 modifications, by MM. Becquerel and Rodier, 2 it will be advantageous here to 

 describe it. The blood which is being drawn for analysis is received into two 

 different vessels, the first and the last quarters of the whole amount into one, and 

 the second and third quarters into the other; in this manner the similarity of 

 the two quantities is secured as far as possible. The blood in one vessel (A) is 

 allowed to coagulate spontaneously ; that contained in the other (B) is beaten 

 with a small rod in order to separate the fibrin. When the coagulation has fully 

 taken place in A, the serum is carefully separated from the crassamentum ; and 

 there are then dried and weighed 1. The Fibrin obtained by the rod (B); 2. 

 The entire Crassamentum (A) ; 3. The Serum (A). The weight of the separated 

 fibrin gives the amount of it contained in the clot. The weight of the dried 

 residue of the serum gives the proportion of its solid matter to its water. The 

 quantity of water driven off from the clot in drying gives the amount of serum 

 it contained ; from which may be estimated the quantity of the solids of the 

 serum contained in the crassamentum. Hence by deducting from the weight of 

 the whole dried clot, first the weight of the fibrin separated by stirring, and then 

 that of the solid matter of the serum as obtained by calculation, we obtain as a 

 residue the weight of the corpuscles. In order to ascertain the whole amount of 

 solid matter in the serum, that which was ascertained by calculation to exist 

 in the coagulum must be added to that which was obtained from the separated 

 serum. Finally, the proportion of organic and of inorganic matter in the solids of 

 the serum is ascertained by incinerating them in a crucible ; by which the whole 

 of the former will be driven off, the latter being left. 



153. A modification of this method, which involves somewhat more trouble 

 in its application, but which is more accurate, has been recently proposed by 

 Scherer. 3 The blood is received, as before, into two separate vessels; and in 

 both of these, which are covered to prevent evaporation, coagulation is allowed 

 to take place. Out of the one (A) is to be determined the composition of the 

 serum, and from the other (B) that of the remaining constituents. Two weighed 

 portions of the serum are taken from the first vessel (A), and one of them is 

 evaporated until all the water is driven off; the residue then represents the 

 entire solid matter of the serum. This, having been weighed, is incinerated ; 

 and the residue then left is the saline matter of the serum. The other portion 

 of the serum is poured into boiling water, and stirred with a glass rod, acetic 

 acid being added, drop by drop, as long as any precipitation continues. The 

 albuminous coagulum is then separated by filtration, dried and weighed ; and 

 the filtered fluid, after being again examined for any albumen that may be left 

 uncoagulated, is evaporated to dryness. The residue, consisting of the extractive 

 with the salts, is incinerated after having been weighed ; and the weight of the 

 salts being thus determined, the difference is that of the extractive matters. 

 The blood in the second vessel (B), after having been weighed, is put upon a fine 

 linen cloth, and carefully squeezed between the fingers until all the fluid is 

 expressed that can be thus separated, and only the solid coagulum remains 

 behind ; this is well washed with distilled water, to get rid of the corpuscles, 

 and the fibrinous residue is dried and weighed. Of the expressed fluid (serum + 

 corpuscles) two portions are again weighed out, as of the serum alone in the 

 previous analysis; one of these serves to determine the relative proportions of 

 the water, of the solid residue, and of the salts; and the other to determine the 



1 " Essai d'Haematologie Pathologique." 



2 " Recherches sur la Composition du Sang, dans 1'etat de Sante, et dans 1'etat de 

 Maladie." 



3 "Canstatt's Jahresbericht," 1848, p. 64; and Haeser's Archiv., band x. p. 191. 



