TISSUES OF THE BODY. 



119 



Fig. 120. Crystals of haemoglobin, from the 

 inea pig (above); from the horse flower 



guine! 

 half). 



of a membrane on the cell. The elements of composition belonging to 

 the red corpuscle are numerous. 



In the first place, the cell-body consists of haemoglobin ( 13), as was 

 already mentioned, divisible into two substances an albuminous and 

 pigmentary, known respectively as globulin ( 12) and hsematin ( 35). 

 The first of these, however, has only been obtained in an impure state, 

 as both bodies defy perfect separa- 

 tion from one another. It appears in 

 the cell in far larger proportion than 

 the colouring matter ; for instance, 

 1000 parts of blood-corpuscles from 

 the horse contain 3 60 '4 of solid con- 

 stituents, of which 19 -9 consist of 

 hsematin and 321-1 of globulin. 



Blood-ci'ystals, which were dis- 

 covered first by Funke in the blood 

 of the splenic vein, have already been 

 discussed ( 13). 



The crystallizing substances of 

 blood-cells are not by any means 

 always identical, a fact which is indi- 

 cated by the greater or less readiness 

 with which crystallization commences 

 in the blood of various species of 

 animals, and which is further corroborated by the varieties in the cry- 

 stalline form (figs. 120, 121). 



The colouring matter of blood is, on account of its composition, into 

 which iron enters, one of the 

 most remarkable substances 

 of our body. Not being met 

 with either in the plasma 

 or the fluids compensating 

 the blood for loss, namely, 

 lymph and chyle/ it must 

 be formed by the chemical 

 activity of the blood-cell by 

 a process still unknown to 

 us. It is not always con- 

 tained in the same amount 

 in the corpuscles, which we 

 might at once infer from the 

 variation in intensity of the 

 tint of isolated cells, which 

 ai-e at one time yellow, an- 

 other of a paler hue. The 

 dilference in the colouring 

 properties of certain kinds of 

 blood when mixed with water 

 points to the same conclusion. 



Fibrino plastic matter (Schmidt) has also been met with in the blood- 

 cell, and, it appears, in no inconsiderable quantity; besides which, 

 lecithin, cerebrin, and cholestearin ( 21) (Hoppe, Hermann) have been 

 met with here. A proposition first made by Berzelius, that the " fatty 



Fig. 121. Haemoglobin trom the squirrel, crystallizing in 

 the hexagonal system. 



