BLOOD. 241 



the dried fibrin we know the quantity of that constituent con- 

 tained in the clot. By weighing the dried serum we know the 

 proportions of water and of soHd constituents contained in it. 

 Lastly, we weigh the dried clot : the quantity of water which it 

 gives off is estimated as serum, and the solid residue due to it is 

 i-eadily calcvdated. By deducting from the weight of the dried 

 clot the weights of the fibrin and of the solid residue of the 

 serum contained in the clot, we obtain the amount of the 

 globules. Hence we have (1) the weight of the fibrin; (2) the 

 weight of the globules ; (3) the weight of the solid residue of 

 the serum ; and (4) the weight of the water. 



This method is simple, and easy of application, in cases in 

 which it is unnecessary to ascertain the proportions of hsematin, 

 globulin, fat, hsemaphsein, extractive matters, and salts, sepa- 

 rately. I shall, however, show that an error may easily arise in 

 the determination of the blood-corpuscles, if the drying has not 

 been perfectly effected. 



In order to ascertain what would be the amount of differences, 

 I analysed the same blood by their method, and by my own. 

 About eight ounces of blood were received in a glass, from the 

 arm of a woman, aged 35 years. It was rapidly stirred ; about 

 a fourth part of it was poured into a small glass, and the 

 fibrin removed in the ordinary manner, by whipping. The 

 larger portion was left to coagulate. 



I. Analysis of the defihrinated blood. 



The blood, including the fibrin, weighed 950 grains, of which 

 the fibrin, when washed and thoroughly dried, weighed 1*9 gr. 

 Hence 1000 parts of blood contain 2*0 of fibrin. 



112-42 grains of defihrinated blood left, after the thorough 

 removal of the water, a solid residue, amounting to 2033 grs. 



Hence 1000 parts of blood contained 180 of solid constitu- 

 ents ; 7'7 grains of the dried residue were boiled in spirit of 

 •925, to which three drops of dilute sulphuric acid were subse- 

 quently added, as long as the spirit continued to take up any- 

 thing more, and until a bright gray-green residue was left. 

 This residue, which is composed of the albumen of the blood, 

 when dried, weighed 3-31 grains. 



The red alcoholic solution was saturated with ammonia, and 

 evaporated to a small residue. The hsematoglobulin, which se- 



16 



