TOO 



DEVELOPMENT OF BLOOD. 



27, 28 and 29) have nearly always a more or less red 

 colour, vary much in size and shape, not only in the blood 

 Fig. 29.* of different animals, 



but in the same 

 blood at different 

 stages of its decom- 

 position, and also 

 present diversities in 

 chemical composi- 

 tion, some being 

 soluble in one re- 

 agent, some in 

 another. The sub- 

 stance of which they 

 are composed has 

 been especially stu- 

 died by Lehmann ; it appears to be of an albuminous 

 nature, and probably results from a retrograde trans- 

 formation of the contents of the red corpuscles, namely, 

 the hcemato-glolulin, or, as it may be now termed, cruoro- 

 glolulin. The globulin, however, seems to be essentially 

 the substance of which most of these crystals are composed ; 

 for Lehmann has obtained them free from colour, but in 

 other respects, apparently unaltered. Cruorin, or a modi- 

 fication of it, is, however, also crystallizable. 



This interesting subject is still involved in some 

 obscurity. 



Development of the Blood. 



In the development of the blood little more can be traced 

 than the processes by which the corpuscles are formed. 

 The first formed blood-cells of the human embryo differ 



* Fig. 29. Hexagonal crystals, from blood of squirrel. On these six- 

 sided plates, prismatic crystals, grouped in a stellate manner, not 

 unfrequently occur (after Funke). 



