162 COMPARATIVE PHYSIOLOGY. 



also phosphate of calcium and magnesium, with rather more 

 of potassium chloride. 



It is highly prohahle that this proportion also represents 

 moderately well the composition of plasma, which is, of course, 

 from a physiological point of view, the important matter. 



The Composition of the Corpuscles.— Taken together, the dif 

 ferent forms of Mood-cells make up from one third to nearly 

 one half the weight of the blood, and of this the red corpuscles 

 may be considered as constituting nearly the whole. 



The colorless cells are known to contain fats and glycogen, 

 which, with salts, we may believe exist in the living cells, and, 

 in addition to the proteids, into which protoplasm resolves it- 

 self upon the disorganization that constitutes its dying, lecithin, 

 protagon, and other extractives. 



The prominent chemical fact connected with the red corpus- 

 cles is their being composed in great part of a peculiar colored 

 proteid compound containing iron. 



This will be fully considered later: but, in the mean time 

 we may state that the haemoglobin is itself infiltrated into the 

 meshes or framework (stroma) of the corpuscle, which latter 

 seems to be composed of a member of the globulin class, so well 

 characterized by solubility in weak saline solutions. 



' The following tabular statement represents the relative pro- 

 portions in 100 parts of the dried organic matter of the red cor- 

 puscles : 



Haemoglobin 90'54 



Proteids 8-67 



Lecithin 0'54 



Cholesterin 0-25 



100-00 

 The quantity of salts is very small, less than one per cent 

 (inorganic). * 



So much for the results of our analyses ; but when we con- 

 sider the part the blood plays in the economy of the body, it 

 must appear that, since the life-work of every cell expresses it- 

 self through this fluid, both as to what it removes and what it 

 adds, the blood can not for any two successive moments be of 

 precisely the same composition ; yet the departures from a nor- 

 mal standard must be kept within very narrow limits, other- 

 wise derangement or possibly death results. We think that, 

 before we have concluded the study of the various organs of 



