122 VARIATIONS IN WATER, ALBUMEN, AND FIBRIN. 



liable to rapid variations, as dependent on the condition of thirst or the 

 recent indulgence in drinks. It does not increase in proportion to the 

 amount which has been imbibed, for the Malpighian bodies of the kidney, 

 as will hereafter appear, strain it off with great rapidity. When the 

 blood-vessels are distended to a certain degree, they refuse an entrance to 

 it. The necessity of these provisions arises from the fact that there is a 

 certain state of viscidity which the blood must possess for its proper cir- 

 culation. 



Eespecting variations in the amount of water in the blood, it may be 

 stated that that of women contains more water than that of men. Among 

 different animals, the serum of the amphibia contains the largest quantity; 

 and among mammals, that of the herbivora more than that of the car- 

 nivora. Obtained from different vessels, the arterial has more than 

 venous blood, but the serum of the portal vein contains more than that 

 of any other vein, the proportion depending on the amount and time of 

 the ingestion of water. 



The albumen varies in quantity from 60 to 70 in 1000. It is prob- 

 Variations in a ^ v associated or combined with soda. It exists in the 

 quantity of ai- blood of the splenic and hepatic veins as the neutral albumi- 

 nate of soda. It does not appear to contain any phosphorus, 

 as was at one time supposed. It is the plastic material from which all 

 the soft tissues are nourished, and by it the cells themselves grow. 

 Fibrin arises from it in the blood in the same manner as it does during 

 the incubation of an egg ; every care is taken to economize it in the sys- 

 tem, and it is never excreted except in disease. 



The quantity of albumen is greater in venous than in arterial blood, 

 the proportion increasing during digestion. It also presents variations 

 in different states of disease. Its condition varies in various parts of the 

 circulation, a circumstance, to a considerable extent, due to the nature of 

 the salts, or to the quantities of alkali with which it is associated. 



The fibrin is usually estimated at 2 or 3 parts in 1000 of blood. It 



Vari tions in mav ^1 as ^ ow as ^ or r ^ se as high a s 7 j. There is a con- 

 the quantity of stant drain upon it for the nutrition of the muscular tissues ; 

 and since it originates in the action of oxygen upon albu- 

 men, we should expect, as is really the case, that arterial blood would be 

 richer in it than venous. The portal blood contains it in minimum quan- 

 tity. Its percentage rises if oxygen be inhaled, or the respiratory pro- 

 cess be quickened ; for similar reasons, it uniformly increases in acute 

 inflammations. The ultimate analyses of fibrin seem to show that it con- 

 tains more oxygen than albumen, and this corresponds with its mode of 

 origin. It is an important practical observation, that though it is easy 

 to regulate the quantity of cells by variations of diet, the amount of 

 fibrin can not so readily be changed in that manner, nor its development 



