234 BLOOD. 



become poorer in globulin and richer in haematin after repeated 

 venesections, when the blood has become more watery. 



Schmidt has drawn up the following table from cases in which 

 three venesections were performed. The first was a case of pneu- 

 monia, in which the blood was analysed by himself; the second 

 was one of tuberculosis; and the nature of the third is not 

 specified. The analysis in the last two cases was made by 

 Becquerel and Rodier. 



Pneumonia. Tuberculosis. Unspecified case. 

 1st venesection .... 248 : 1 256 : 1 252 : 1 



2nd .... 233 : 1 252 : 1 247 : 1 



3rd .... 221 ; 1 234 : 1 212 : 1 



The relative quantity of iron contained in the blood-corpuscles 

 increases,, therefore, with each successive venesection. This 

 phenomenon admits of a simple solution, for it would appear, 

 from all observations, that the heematin cannot permeate the 

 walls of the blood-cells, which, however, admit of the permeation 

 of their albuminous contents : now if the blood loses solid con- 

 stituents, the serum becomes richer in water ; a diffusion-current of 

 a more diluted solution then enters the blood-cells, whilst a more 

 concentrated stream passes outwards from them; now since haematin 

 cannot penetrate through the cell-wall, the loss of solid con- 

 stituents from the blood-cell must mainly affect the globulin, 

 whilst the hsematin will, under such conditions, appear to be 

 relatively increased in relation to the globulin + the cell- 

 membrane. 



I found the quantity of hsematin in the cells of the arterial 

 blood of the horse somewhat more considerable than that contained 

 in the blood of the external jugular veins ; whilst, on the other 

 hand, the quantity of heematin contained in the blood-cells of the 

 hepatic veins is far smaller than that of the portal blood. 



I found the ratio of iron to the dried blood-corpuscles in the 

 arterial blood of the horse, as 1 : 394 ; in the jugular vein, as 

 1 : 390; in the portal vein, as 1 : 312; and in the hepatic veins, 

 as 1 : 500; these being the mean results obtained from several 

 experiments. The smaller quantity of heematin contained in the 

 cells of the arterial blood, compared with those of the jugular 

 venous blood may be referred not only to the greater richness in 

 fat of the arterial blood, but more decidedly, or even exclusively, 

 to the loss of fat which takes place during the arterialization of 

 venous blood by the process of respiration. 



