CHAPTER XV 



THE CHEMICAL COMPOSITION OF THE BLOOD 



The Composition of Whole Blood. 1 It must be admitted that it 

 is almost impossible at the present time to obtain exact analytical 

 data regarding the composition of the blood on account of its tendency 

 to coagulate, and, because its composition varies not only in different 

 species, but also in animals of the same group. Besides, considerable 

 divergences may be encountered in one and the same animal, in accord- 

 ance with the location or functional importance of the vessels from 

 which the blood is withdrawn. Lastly, it is entirely probable that the 

 methods used at the present time are altogether too crude to allow 

 us to detect its more intricate chemical peculiarities. 



Under ordinary conditions, human blood contains 77 to 82 per cent, of water, 

 and 18 to 23 per cent, of solids. The latter include 17.3 to 22.0 per cent, of organic 

 and 0.6 to 1.0 per cent, of inorganic material. Proteins and hemoglobin form by 

 far the largest amount of the organic mass; 13 to 15 per cent, being the value for 

 hemoglobin alone. In the ox, sheep, goat, and rabbit the hemoglobin content is 

 lower than in man, while in the dog, horse, cat and pig it is equal to it. The 



THE COMPOSITION OF DOG'S BLOOD 



1 Oppenheimer Handb. der, Biochemie, Jena, 1909. 

 168 



