70 



THE BLOOD. 



nitrous oxides, with all of which it appears to form definite 

 chemical combinations. The combination with oxygen is that 

 which is of most physiological inportance. During the passage 

 of the blood through the lungs, it is constantly formed; while 

 it is as constantly decomposed, in consequence of the readiness 

 with which haemoglobin parts with oxygen, when the latter is 



FIG. 27. 



Tetrahedral, from blood of the guinea-pig. 



exposed to other attractions in its circulation through the sys- 

 temic capillaries. Thus, the red corpuscles, in virtue of their 

 coloring matter, which readily absorbs oxygen and as readily 



FIG. 28. 



Hexagonal crystals, from blood of squirrel. On these six-sided plates, prismatic 

 crystals, grouped in a stellate manner, not unfrequently occur (after Funke). 



