COMPOSITION OF THE BLOOD-CELLS. 235 



In speaking of the formation of blood-cells in the liver, we 

 drew attention to the fact that a small portion of the iron which 

 was conveyed to that organ with the blood-cells of the portal vein, 

 is separated with the bile, while the remaining portion appears to 

 be equably distributed among the blood- corpuscles which have 

 been newly formed within the liver, so that the iron of 100 blood- 

 corpuscles of the portal vein is distributed over nearly 150 

 corpuscles of the hepatic veins : consequently the blood-cells of 

 the hepatic veins must contain one-third less iron than that of the 

 portal vein. 



The blood-corpuscles must necessarily also exhibit differences 

 in their amount of fat, since the quantity of fat contained in the 

 blood of different animals and of men, under different conditions, is 

 extremely variable. In reference to this question, I have directed 

 special attention to the differences in the quantity of fat contained 

 in the blood-corpuscles of different vessels of the same animal ; 

 and the results of my investigations, taking the mean of several ex- 

 periments, are, that 1 00 parts of moist blood-cells from the carotid 

 artery of a horse contain 0*608 of fat; 100 parts from the external 

 jugular vein, 0*652; from the portal vein, 0*752 ; and from the 

 hepatic veins, 0*684. These experiments warrant us in hoping 

 that a further prosecution of such inquiries may throw a very con- 

 siderable amount of light on the metamorphosis of fat, and on 

 the function of the blood-cells. The first step seems, at all events, 

 to have been made towards the elucidation of that chemical meta- 

 morphosis which the blood-cells experience in the pulmonary 

 capillaries by the action of the inspired oxygen. 



That the blood- corpuscles contain variable quantities of soluble 

 salts, is a fact that is made evident by the above mentioned inves- 

 tigations of C. Schmidt, in which he ascertained the different 

 proportions of the potash salts and phosphates in the blood-cells 

 to the soda and chlorine compounds in the serum of the blood of 

 different species of animals. But I also found that the quantity of 

 salts contained in the cells of the blood from different vessels of the 

 same animal constantly differed ; thus, for instance, 100 grammes 

 of fresh blood-cells from the temporal artery of a horse contained 

 0*806 of a gramme of salts (independently of the peroxide of iron 

 in the ash) ; the same quantity, taken from the external jugular 

 vein, contained 0*632, from the portal vein 0*729, and from the 

 hepatic veins 0*893. There is therefore a very considerable 

 difference, in reference to their amount of salts, between the cells 

 of the arterial and those of the venous blood ; the former contain- 



