60 THE HUMAN BODY. 



amount of fats present, instead of being colorless or pale yel- 

 low and transparent as it is after fasting. The salts dissolved 

 in the serum are mainly sodium chloride and carbonate; 

 small quantities of sodium, calcium, and magnesium phos- 

 phates are also present. 



Chemistry of the Red Corpuscles. In these in the fresh 

 moist state there are, in 100 parts, 56 of water and 44 of 

 solids. Of the solids about one per cent is salts, chiefly potas- 

 sium phosphate and chloride. The remaining solids contain, 

 in 100 parts, 90 of hsemoglobin and about 8 of other proteids; 

 the residue consists of less well-known bodies. 



Chemistry of the White Corpuscles. Besides much water, 

 these yield several proteids, some fats, glycogen (see Chap. 

 XXIX) and salts; and smaller quantities of other bodies. 

 The predominant salts, like those of the red corpuscles, are 

 potassium phosphates. 



Variations in the Composition of the Blood. The above 

 statements refer only to the average composition of the 

 healthy blood and to its better known constituents. From 

 what was said in the last chapter it is clear that the blood 

 flowing from any organ will have lost or gained, or gained 

 some things and lost others, when compared with the blood 

 which entered it. But the losses and gains in particular parts 

 of the Body are in such small amount as, with the exception 

 of the blood-gases, to elude analysis for the most part: and 

 the blood from all parts being mixed in the heart, they 

 balance one another and produce a tolerably constant average. 

 In health, however, the specific gravity of the blood may vary 

 from 1045 to 1075; the red corpuscles also are present in 

 greater proportion to the plasma after a meal than before it. 

 Healthy sleep in proper amount leads to increase in the pro- 

 portion of red corpuscles, and want of it tends to diminution 

 of their number, as may be recognized in the pallid aspect of 

 a person who has lost several nights' rest. 



The proportion of the red corpuscles has a great impor- 

 tance since, as we shall subsequently see, they serve to carry 

 oxygen, which is necessary for the performance of its func- 

 tions, all over the Body. Ancemia is a diseased condition 

 characterized by pallor due to deficiency of red blood-corpus- 

 cles, and accompanied by languor and listlessness. It is not 

 unfrequent in girls on the verge of womanhood, and in per 



