122 THE BILE. 



3. To confirm the results, or, if the stain is too small 

 to obtain them, try to obtain the haemin crystals as in 

 Experiment 253. After applying the acid to the dried 

 mass the latter should be broken up with a glass rod to 

 insure thorough mixture. If it is very hard let it soak in 

 the acid for a short time. These haemin crystals are pro- 

 duced only from the coloring matters of the blood. When 

 in doubt as to their identity they should be compared with 

 those obtained from known blood, remembering that dif- 

 ferent specimens of crystals may differ considerably in 

 size. 



4. If there is a sufficient amount of the blood, not 

 too long exposed to the air, or if it is desirable to de- 

 termine the species of animal, it may be soaked in a small 

 amount of 1 / 2 -per-cent.-salt solution and the appearance 

 and size of the corpuscles compared with those of known 

 specimens or measured by a microscope with a micrometer 

 eye-piece. 



THE BILE. 



The bile is normally a brown to greenish, viscid fluid 

 with a bitter taste and a neutral or slightly alkaline re- 

 action. It is a mixture of the secretions of the liver-cells 

 with that from the mucous membrane of the passages, 

 which latter contains a viscous substance similar to the 

 nucleoalbumins. This is usually called biliary mucin, al- 

 though it differs in some respects from true mucin. 



The compounds which make up the larger part of 

 the solid matters of the bile are the sodium salts of gly- 

 cocholic and taurocholic acids. Besides these and the 

 biliary mucin there are present fats, soaps, lecithin, and 

 cholesterin, also a number of inorganic salts of the alka- 



