THE BLOOD. 107 



than serum. For human blood ARRONET has found 478.8 p. m. 

 blood -corpuscles and 521.2 p. m. serum (in defibrinated blood) as 

 an average of nine determinations. 



The relative amount of blood-corpuscles and plasma therefore 

 varies. In human blood the plasma is about 50$ of the weight of 

 the blood; but in other cases it seems generally to be somewhat 

 greater. In a few cases it may indeed be f of the weight of the 

 blood. Water occurs in the greatest amount in the plasma or serum, 

 which latter ordinarily contains at least -f$ water, while the blood- 

 corpuscles contains only a little more than or about f water. 

 Iron probably occurs only in the blood-corpuscles. Chlorine and 

 eodium prevail generally in the plasma, potassium and phosphoric 

 acid in the blood-corpuscles. In a few varieties of blood (pig's 

 and horse's blood) the sodium is found exclusively in the plasma or 

 serum, the potassium prevailing in the blood-corpuscles (BuNGE). 

 In dog's and ox's blood the blood-corpuscles are, however, richer 

 in sodium than in potassium (Bu^GE). In man the potassium 

 is contained in the largest quantities in the blood-corpuscles 

 and only in very small quantities in the plasma (C. SCHMIDT, 

 WANACH). The alkaline earths occur chiefly in the plasma. 

 Manganese has also been found in the blood (0.06 p. m. according 

 to BURIN DE BUISSON"), as well as traces of lithium, copper, lead, and 

 silver. The blood as a whole contains in ordinary cases 770-820 

 p. m. water, with 180-230 p. m. solids; of these 173-220 p. m. 

 are organic and 6-10 p. m. inorganic. The organic consist, de- 

 ducting 6-12 p. m. extractive bodies, of albumin and haemoglobin. 

 The amount of these last-mentioned bodies in the blood is about 

 130-150 p. m. 



The amount of sugar in the blood is on an average 1-1.5 p. m. 

 The quantity of urea, which amounts to 0.2-0.9 p. m., is greater 

 after partaking of food than during fasting (GREHANT and QUIK- 

 QUAUD). The quantity of uric acid may be 0.1 p. m. in bird's blood 

 (v. SCHRODER), and the quantity of lactic acid may reach 0.71 p. 

 m. in human venous blood (BERLINERBLAU). 



