DISINTEGRATION OF THE BLOOD-CELLS. 279 



estimate of the period of their duration, if it were not that both 

 these substances were employed in the experiment in a state of 

 purity, whilst in the lungs the blood-corpuscles are only acted 

 upon by atmospheric air containing about 4 of carbonic acid. We 

 may presume from a comparison of the blood taken in repeated 

 venesections, that the period of duration or existence of the red 

 corpuscles is not very short ; for the circumstance that the blood 

 continues for several days after a moderate venesection to be poor 

 in corpuscles, and even exhibits a great deficiency of these bodies 

 for a prolonged period after repeated venesections, certainly proves 

 that their regeneration is not effected with great rapidity. If, 

 however, they are slowly regenerated, as appears to be the case, 

 judging from the copious supply of colourless cells in the circulating 

 fluid after severe losses of blood, they cannot have a very short ex- 

 istence, for otherwise the number of the coloured cells would not so 

 far exceed that of the colourless corpuscles. 



The question, whether the blood-corpuscles are disintegrated at 

 one definite spot, has not yet been decided with any certainty. It 

 was generally supposed by the earlier observers, that the destruction 

 of the blood-corpuscles was effected by the alternating action of 

 oxygen and carbonic acid, as well as of different salts and other 

 substances, this action being gradually continued throughout the 

 whole course of the blood-vessels, and their products also under* 

 going a gradual solution. As the arterial blood has been found to 

 be poorer in corpuscles than the venous, some support seemed to 

 be afforded to the view that the older blood-cells were principally 

 destroyed in the capillaries of the lungs by the access of oxygen ; 

 but as it has been only proved that the weight of the sum of the 

 blood-cells is diminished, and not that their number is lessened, 

 we are by no means compelled to assume that the blood-cells are 

 destroyed in the arteries ; and it would even appear probable, on 

 many grounds, that the weight of each cell is diminished by respi- 

 ration, but not that the whole number is lessened. There seems, how- 

 ever, to have been a disposition to connect the disintegration of the 

 blood-cells with one definite locality, and Schultz more especially de- 

 signated the liver as the organ in which this process was effected. 

 F. C. Schmid's more accurate investigations of the portal blood and 

 of the coloured cells contained in it, which differ from those of other 

 blood, appear indeed to afford a more exact foundation for this 

 hypothesis. We have already spoken at length of the constitution 

 of the portal blood and of its relation to the hepatic function, in the 

 chapters on "bile" and on "the blood/ 5 and from our comparative 



