PLASMA OF THE BLOOD. 257 



small veins, when imprisoned in a stagnant portion of the blood-plasma. 

 But if the circulation be re-established, and the globules again move 

 with the blood current, they cease to be distorted, and resume their 

 original rounded form. 



The precise physiological properties and functions of the white cor- 

 puscles cannot be determined so distinctly as in the case of the red 

 globules. Their great inferiority in number shows that they are less 

 important for the immediate continuance of the vital operations ; and 

 the same thing may be inferred from their want of strongly marked spe- 

 cific characters. For while the red globules of the blood vary in ap- 

 pearance to a marked degree in different classes and orders of animals, 

 the white globules present nearly the same general features of size, form, 

 and structure throughout the series of vertebrate animals. 



Plasma of the Blood. 



The plasma of the blood is the transparent, colorless, homogeneous 

 liquid, in which the blood-globules are held in suspension. It consists 

 of water, holding in solution various mineral salts, and of certain albu- 

 minous matters, which are distinguished by their modes of coagulation, 

 the principal of which are known as fibrine and albumen. 



Ths plasma of the blood, according to the estimates of Lehmann and 

 Robin, has, on the average, the following constitution : 



COMPOSITION OF THE BLOOD-PLASMA. 



Water 902.00 



Albumen .......... 75.00 



Fibrine 3.00 



Fatty matters 2.50 



Crystallizable nitrogenous matters 4.00 



Other organic ingredients . 5.00 



Sodium chloride 



Potassium chloride 



Sodium carbonate 



Sodium and potassium sulphates 



Sodium and potassium phosphates 



Lime and magnesium phosphates j 



Mineral salts 8.50 



1000.00 



The above ingredients are all intimately mingled in the blood-plasma, 

 in a fluid form, by mutual solution ; but they may be separated from 

 each other for examination by appropriate means. The two ingredients 

 which on account of their nature and properties have received the 

 greatest attention, are the fibrine and the albumen. 



The fibrine cannot be obtained for examination under the form in 

 which it naturally exists in the blood, since it is only to be separated 

 from the other albuminous ingredients by undergoing the process of 

 coagulation. Notwithstanding that this substance, or the material from 

 which it is derived, is present in the blood in so small a quantity as 

 three parts per thousand, it is evidently an important element in the 



