236 



TEXT-BOOK OF PHYSIOLOGY. 



late beyond a small amount, since they are constantly being elimi- 

 nated from the blood by the various excretory organs. 



Inorganic Salts. The inorganic salts of the plasma are chiefly 

 sodium and potassium chlorids, sulphates, and phosphates, together 

 with calcium and magnesium phosphates. Of the salts, sodium 

 chlorid is the Post abundant, amounting to 5.5 parts per thousand. 

 Some of the- sails are- alkaline and impart to the blood its alkalinity. 

 Calcium phosphate is present in small quantity -2 jparls, per i OOP. 

 This salt is wanting in serum for the reason that it became a constitu- 

 ent of fibrin at the time of coagulation. In other respects serum 

 differs but slightly from plasma in the proportions of its saline con- 

 stituents. 



HISTOLOGY OF THE RED CORPUSCLES OR ERYTHROCYTES. 



The histologic features of the red corpuscles are readily observed 

 in a drop of freshly drawn blood when examined microscopically. 

 The field of the microscope will be seen to be crowded with red cor- 

 puscles floating in a clear transparent fluid the plasma. Here and 



there will also be seen a 

 white corpuscle, round or 

 irregular in shape, and 

 granular in appearance. 

 Within a short time a 

 characteristic phenomenon 

 takes place: viz., the ar- 

 ranging of the corpuscles 

 in the form of columns of 

 varying length, resembling 

 rolls of coins. These rolls 

 interlace with each other at 

 all angles and form a net- 

 work in the meshes of 

 which lie individual red 

 and white corpuscles. (See 

 FIG. 96. CORPUSCLES FROM HUMAN SUB- Fig. 96.) The cause of 

 JECT. A few colorless corpuscles are ^:~ f^nrlpnrv nf tV.A rnr 

 seen among the colored discs, many of 11S tendency O the COr- 



which are arranged in rouleaux. puscles to adhere to one 



C*""*0 another is not definitely 



known y Since it does not 



take place in circulating blood/ and since it is to a great extent 

 prevented by defibrinating the blood, it has been supposed to be 

 dependent on the formation of some adhesive substance connected 

 with the formation of fibrin. 



Color. When viewed by .transmitted light, a single corpuscle 

 is slightly yellow or greenish in color; but when a number are grouped 



