BLOOD. 



475 



The most important constituent of the red blood-corpuscles, both in 

 quantity and function, is the " haemoglobin." Haemoglobin, or the blood 

 coloring-matter, is a complicated, crystallizable albuminoid body 

 containing iron, and forms about 90 per cent, of the red blood-cells. 

 When separated from the corpuscles, haemoglobin readily crystallizes out 



1 



Mb, 



Fig. 176.— Blood-Crystals of Max and Different Animals. (Thanhoffer and Frey.) 



I, hzemoglobin crystals; Mo, squirrel ; Tr, guinea-pig ; U, ground-mole ; L, horse; Em, man ; H, 

 marmot; Ma, cat; T, cow; mv, from the venous blood of a eat. 2, haematin crystals ; E, man; Vb, 

 sparrow ; M, eat. 3, hasmatoidin crystals from an old blood extravasation of man. 



of its solutions in serum when concentrated. These crystals have dif- 

 ferent forms in different species of animals, depending, apparently, on 

 varying amounts of water of crystallization. In the domestic animals they 

 belong to the rhombic system ; those of the squirrel are hexagonal. The 



