88 THE BLOOD. 



appears to be deficient in solid matters, especially in red 

 corpuscles, owing to dilution by the quantity of water ab- 

 sorbed, to contain an excess of albumen, though chiefly of 

 a lower kind than usual, resulting from the digestion of ni- 

 trogenised substances, and termed albuminose, and to yield 

 a less tenacious kind of fibrin than that of blood generally. 



The blood from the splenic.vein is probably more definite 

 in composition, though also liable to alterations according 

 to the stage of the digestive process, and other circum- 

 stances. It seems generally to be deficient in red cor- 

 puscles, and to contain an unusually large proportion of 

 albumen. The fibrin seems to vary in relative amount, 

 but to be almost always above the average. The propor- 

 tion of colourless corpuscles appears also to be unusually 

 large. The whole quantity of solid matter is decreased, 

 the diminution appearing to be chiefly in the proportion 

 of red corpuscles. 



The blood of the portal vein, combining the peculiarities 

 of its two factors, the splenic and mesenteric venous 

 blood, is usually of lower specific gravity than blood 

 generally, is more watery, contains fewer red corpuscles, 

 more albumen, chiefly in the form of albuminose, and 

 yields a less firm clot than that yielded by other blood, 

 owing to the deficient tenacity of its fibrin. These 

 characteristics of portal blood refer to the composition of 

 the blood itself, and have no reference to the extraneous 

 substances, such as the absorbed materials of the food, 

 which it may contain ; neither, indeed, has any complete 

 analysis of these been given. 



Comparative analyses of blood in the portal vein and 

 blood in the hepatic veins have also been frequently made, 

 with the view of determining the changes which this fluid 

 undergoes in its transit through the liver. Great diversity, 

 however, is observable in the analyses of these two kinds 

 of blood by different chemists. Part of this diversity is no 

 doubt attributable to the fact pointed out by Bernard, that 



