FUNCTION OF THE BLOOD-CELLS. 277 



constituents and thus directly gives rise to the formation of car- 

 bonic acid in the capillaries. Both these modes undoubtedly occur; 

 for the greater part of the oxygen absorbed in the lungs is only 

 mechanically taken up by the corpuscles,, or is brought to the 

 capillaries in a slightly combined form, as is clearly proved by the 

 experiments of Magnus, Marchand, and others ; but it would be 

 very singular if the blood-cells, which are so susceptible to external 

 influences as, for instance, to chemical agents and which undoubt- 

 edly manifest an active metamorphosis of matter, should remain 

 wholly unaffected by oxygen. This is, however, by no means the 

 case, as we learn from direct observations. We have already shown, 

 and purpose making still more evident by a special reference to 

 analyses, that the difference in the chemical constitution of the 

 arterial and venous blood- corpuscles can scarcely be explained 

 except by the assumption of a chemical action of the oxygen upon 

 the individual organic constituents of the blood-corpuscles in the 

 lungs. We would here only observe, that we found the mineral 

 substances and the hsematin augmented in the blood-corpuscles 

 after the inspiration of oxygen, whilst the organic substances, and 

 more especially the fats, were considerably diminished. This incon- 

 testible fact can scarcely be explained, excepting by the supposition 

 that it is only the mineral substances and the haematin which increase 

 in weight by the absorption of oxygen, whilst the organic substances, 

 and more especially the fats, are either destroyed by oxidation, and 

 their products of decomposition transferred to the intercellular 

 fluid, or at all events they undergo a considerable diminution of 

 weight by the formation of water and carbonic acid. No one, how- 

 ever, can seriously believe that the blood-corpuscles swim un- 

 changed, like mechanical molecules, from the capillaries of the 

 lesser to those of the greater circulation. 



Although we are not yet able to express the function of the 

 blood-cells in exact chemical equations, and therefore cannot com- 

 prehend their precise physiological import, we may yet, from the 

 facts at our disposal, form some general opinion in reference to the 

 purpose of their existence in the blood. The blood-corpuscles are 

 cells having special contents, whose existence cannot be conceived 

 on physical grounds without a simultaneous and continuous 

 metamorphosis of matter. Their activity must correspond to the 

 menstruum in which they are suspended, and to all the relations 

 generally in which they occur in the living body. We must, 

 a priori, conclude that each recent animal cell in the healthy blood 

 is, under given relations, metamorphosed into blood-corpuscles, 

 precisely as we see the primary type of the animal cell, the chyle- 



