THE BLOOD. 497 



and as the material for the formation of its principal 

 ingredients, prepared or "formed by digestion from the 

 foocf, is constantly added in the form of chyle and 

 lymph, which are emptied into it ; it must contain 

 many other substances besides the principal ingredi- 

 ents. The discovery and recognition of these have, 

 however, been but very imperfectly successful. 



When blood is subjected to microscopical investiga- 

 tion, two other kinds of spherical bodies are seen 

 besides the blood-corpuscles. These are colorless, pre- 

 sent in less abundance, and some of them smaller than 

 the corpuscles. The smaller ones are drops of fat, the 

 larger (so-called colorless blood-corpuscles) are the 

 lymph- or chyle-corpuscles. In the chemical analysis 

 of blood, as difficult and imperfect as it is as yet, 

 several other substances besides the principal ingre- 

 dients are found. 



Different kinds of fat are found in it, but in small 

 quantity, partially suspended as minute drops, par- 

 tially in solution in saponaceous combination ; and also 

 cholesterin (p. 480). 



The liquid, which remains over after the coagulation 

 of the blood by heating, leaves behind a yellow, ex- 

 tract-like mass when evaporated, consisting of a mix- 

 ture of organic substances and salts. Urea and succinic 

 acid belong to the first, the latter are principally 

 sodium chloride and salts of potassium and sodium 

 with fatty acids, phosphoric acid, and sulphuric acid. 

 In carnivorous animals sodium phosphate is principally 

 found ; in graminivorous, sodium carbonate at the same 

 time. Analyzed as a whole, blood has nearly the same 

 elementary composition as the organic muscular sub- 

 stance, as a whole, of the same animal, and contains 

 also the same amount of inorganic ingredients. 



1000 parts by weight of blood-corpuscles contain 

 688 parts of water and~312 of solid ingredients. Of the 

 latter 8-9 parts are inorganic salts, not reckoning the 

 iron of haemoglobin. 



1000 parts by weight of serum contain 903 of water 

 and 97 of solid ingredients ; of the latter 8.5 parts are 



inorganic salts. 



42* 



