56 NORMAL HISTOLOGY. 



corpuscles occupy about fifty per cent of the volume of the blood 

 in man,, thirty-five per cent in woman. The volume of the white 

 corpuscles is about two per cent. 



Colored corpuscles, In the blood of man these are usually 

 styled red discs ; as seen on edge, they appear to bulge at the ex- 

 tremities and have concave centers. They are devoid of cell-wall, 

 and on account of their flexibility are capable of crowding through 

 very narrow spaces. 



In the fish, salamander, reptile, and. bird the red corpuscle is 

 nucleated and bi-convex. Among mammals, including man, it is 

 bi-eoncave and non-nucleated. Under the microscope the color ap- 

 pears jrellowish. The red corpuscles are smooth and flexible. Their 

 color is due to the Ji&maglobin, which is suspended in the pores of 

 the stroma, or ground substance, of the corpuscle. The haBmaglobin 

 contains iron, which has a strong affinity for oxygen, forming with 

 that element oxyk&maglobin, which gives to the blood its bright red 

 tinge. The dark color of the venous blood is due, therefore, to 

 the haBmaglobin. The chief function of the red corpuscles is to 

 serve as a carrier of oxygen. When exposed to the air the red discs 

 arrange themselves in rows or stacks, which is called the formation 

 of rouleaux. Water will remove the haemaglobin. Sirup causes the 

 corpuscles to shrivel. Normal saline produces crenation, due to the 

 fact that the salt has an affinity for the stroma and produces con- 

 tractions upon the surface by exosmosis. The red corpuscles are 

 manufactured in the liver, spleen, and red marrow of the bone. When 

 first formed they are nucleated, but afterwards lose their nuclei by 

 mitosis. 



The size of the red disc in man is ^Vir of an inch, or about 

 7.5 p. It would require 40,000 of them to cover the head of a pin. 

 There are about 350 colored discs to one leucocyte. 



Colorless corpuscles. The white corpuscles consist of the pla- 

 telets and leucocytes. The platelets are colorless elements, about 

 TTJVfr ^ an mc ^ m diameter. They are sometimes very abundant. 

 In man the leucocytes are spherical in shape, nucleated, and 

 larger than the platelets and red disks. They are alive and ex- 

 hibit the amoeboid movement, throwing out pseudopodia, by means 

 of which they move from place to place. There are four impor- 



