ORGANIC PRINCIPLES. 85 



expense of the instrument, and a certain dexterity which is 

 necessary for its exact application. 



Origin and Function of Albumen. The albumen of the 

 blood has its origin from a catalytic transformation of the 

 products of digestion of the albuminoid elements of food. 

 It forms the great organic nutrient element of the blood. As 

 we have already seen, it seems to be used in the formation 

 of the fibrin. In nutrition, it undergoes catalytic transfor- 

 mations which result in the peculiar organic principles of the 

 various tissues. In the circulating blood there seems to be 

 a union of the fibrin and albumen which is necessary to the 

 nutritive properties of the latter. Bernard has shown 1 that 

 the albumen of white of egg injected into the veins of an 

 animal is incapable of assimilation, and is therefore rejected 

 by the kidneys. The same result follows the injection of 

 fresh serum, even from an animal of the same species ; but 

 the blood itself, containing both albumen and fibrin, can be 

 injected without the appearance of albumen in the urine, show- 

 ing that in this state it is capable of being used in nutrition. 



In the passage of the blood through the liver, it has been 

 found that a small quantity of albumen disappears ; but, as 

 in the case of fibrin, we have not been able to follow its 

 transformations. With the exception of the minute quantity 

 which is discharged in the milk during lactation, albumen is 

 never discharged from the body in health. After being 

 appropriated by the tissues in the process of nutrition, it 

 undergoes changes in the wearing out of the system, which 

 convert it into excrementitious matter. 



Albuminose. 



This principle is intermediate between the organic nitro- 

 genized elements of food and the albumen of the blood. It 

 is found in the blood in very small quantity after digestion, 



1 BERNARD, Lefons sur les Proprietes Physiologiques et les Alterations Pa- 

 tliologiques des Liquides de V Organisme, Paris, 1859, tome i., p. 467. 



