190 CIRCULATING FLUIDS: 



of blood, their exact determination is no easy matter. All 

 that is known upon the subject is already given in the Intro- 

 duction. 



[A simple method of determining some of the most important 

 constituents of the blood has been recently given by Figuier. 

 It is based on the fact, made known many years ago by 

 Berzelius, that after the addition of a solution of a neutral salt 

 to defibrinated blood, the globules do not (as before) pass through 

 filtering paper. On the addition of two parts of a solution of sul- 

 phate of soda of spec. grav. 1*130 to one of blood, Figuier found 

 that the whole of the corpuscles remained on the surface of the 

 filter. The following are the steps of his analysis. The fibrin 

 is removed by whipping, dried, and weighed; the weight of the 

 corpuscles is ascertained by the method indicated ; and that of 

 the albumen by coagulating, by means of heat, the filtered 

 solution. The proportion of water is determined by evapo- 

 rating a small known weight of the blood.] 



Analysis of coagulated blood. 



It sometimes happens that we receive blood for analysis that 

 has already coagulated. The process to be adopted in such 

 cases, although not in reality more difficult, involves a greater 

 amount of chemical manipulation than when the fibrin is sepa- 

 rated by whipping ; and it appears to give less exact results. 



The directions that I shall now give for the analysis of co- 

 agulated blood were published in a paper of mine some time 

 agoj^ I have, however, only once adopted this method, as I 

 always prefer analysing the blood directly it is taken from 

 the body. 



The whole of the blood must first be weighed as accm'ately 

 as possible, the clot must then be removed, and if sufficiently 

 consistent, dried between folds of blotting paper, and then 

 weighed. A portion of the clot (from 40 to 80 grains) is cut 

 off, and its weight accurately taken ; it is then thoroughly 

 dried, and the loss of weight, which indicates the quantity of 

 water, ascertained : the dried residue must be reduced to a 

 spongy, bright-red fine powder, and treated with ether in order 

 to remove the fat : it must siibsequently be treated with boiling 



' Brande's Archiv, vol. 28. 



