240 BLOOD. 



In regard to the quantity of water in the serum of blood from 

 different vessels, the following may at all events be laid down as a 

 general rule : the serum of arterial blood is more watery, and hence 

 specifically lighter, than that of venous blood, according to the 

 experience of most observers (although Lecanu and Letellier 

 maintain the contrary) ; in the serum of the blood of the temporal 

 artery of a horse I recently found 89'333, and in that of the 

 external jugular vein 86'822-g- of water. Zimmermann* found 

 the serum of the veins of the lower or hinder extremities (of men 

 and animals) poorer in water than the upper or anterior ones. 



The serum of the portal vein is richer in water than that of any 

 other vein, according to the unanimous opinions of Schultz, 

 Simon, and F. C. Schmid, who have all experimented on the sub- 

 ject. My own experiments lead me to believe that this depends 

 both on whether or not the process of digestion was going on at 

 the time, and on whether or not the animals had taken much fluid 

 shortly before their death. Under these different relations I found 

 from 92-342 to 88'684g- of water in the serum of portal blood. 

 The serum of hepatic venous blood is always far richer in solid 

 constituents than that of portal blood ; in five cases I found the 

 quantity of water in the latter to vary between 89'420J and 

 89'298, a result whose importance in relation to the function of 

 the liver has already been noticed (see p. 103). 



This leads us to revert to the relation which the amount of 

 water in the serum and in the blood generally bears to the number 

 of blood-corpuscles. It is a striking phenomenon, that ordinarily 

 a blood whose serum contains much water, presents few corpus- 

 cles ; we observe this in blood under various physiological 

 relations (and even in the blood taken from different vessels), 

 but especially in morbid blood ; hence, the richer a specimen of 

 blood is in water, so much the more serum or intercellular fluid 

 does it contain : if, however, this is a general rule, it is by no 

 means a law, for we not only meet with exceptions to it, but the 

 most accurate analyses made with special reference to this point 

 fail to establish any constant ratio. Thus, for instance, in hepatic 

 venous blood there may be from 137 to 351 parts of fresh blood- 

 cells associated with 100 parts of serum containing from 89*3 to 

 89-4 of water. In morbid blood we still more often meet with 

 similar cases. Hence neither of these properties of the blood 

 depends upon the other, but they are co-ordinate phenomena; 

 * Arch. f. phys. Heilk. Bd. 6, S. 587-600. 



