A HISTORY OF SCIENCE 



and which was named haemoglobin a substance which 

 has a marvellous affinity for oxygen, seizing on it 

 eagerly at the lungs, yet giving it up with equal readi- 

 ness when coursing among the remote cells of the body. 

 When freighted with oxygen it becomes oxyha:-moglo- 

 bin and is red in color; when freed from its oxygen it 

 takes a purple hue; hence the widely different appear- 

 ance of arterial and venous blood, which so puzzled 

 the early physiologists. 



This proof of the vitally important role played by 

 the red -blood corpuscles led, naturally, to renewed 

 studies of these infinitesimal bodies. It was found 

 that they may vary greatly in number at different 

 periods in the life of the same individual, proving that 

 they may be both developed and destroyed in the adult 

 organism. Indeed, extended observations left no 

 reason to doubt that the process of corpuscle forma- 

 tion and destruction may be a perfectly normal one 

 that, in short, every red -blood corpuscle runs its course 

 and dies like any more elaborate organism. They are 

 formed constantly in the red marrow of bones, and are 

 destroyed in the liver, where they contribute to the 

 formation of the coloring matter of the bile. Whether 

 there are other seats of such manufacture and destruc- 

 tion of the corpuscles is not yet fully determined. 

 Nor are histologists agreed as to whether the red -blood 

 corpuscles themselves are to be regarded as true cells, 

 or merely as fragments of cells budded out from a true 

 cell for a special purpose; but in either case there is 

 not the slightest doubt that the chief function of the 

 red corpuscle is to carry oxygen. 



If the oxygen is taken to the tiltirnate cells before 



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