BLOOD-CRYSTALS. 



75 



Fig. 26. ' 



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

 definite chemical combinations. The combination with 

 oxygen is that which 

 is of most physio- 

 logical importance. 

 During the passage 

 of the blood through 

 the lungs, it is con- 

 stantly formed ; while 

 it is as constantly 

 decomposed, in con- 

 sequence of the rea- 

 diness with which 

 haemoglobin parts 

 with oxygen, when 

 the latter is exposed 

 to other attractions 

 in its circulation 

 through the sys- 

 temic capillaries. 

 Thus, the red cor- 

 puscles, in virtue of 

 their colouring mat- 

 ter, which readily 

 absorbs oxygen and 

 as readily gives it 

 up again, are the 

 chief means by which 

 oxygen is carried in 

 the blood (see also 

 p. 8 5 ). 



Fig. 27.1 



* Figs. 26 , 27, and 28, illustrate some of the principal forms of 

 blood-crystals : 



Fig. 26, Prismatic, from human blood. 



t Fig. 27, Tetrahedral, from blood of the guinea-pig. 



