ELEMENTARY CHEMICAL PHYSIOLOGY 



235 



alkaline, if necessary, by a further addition of ^- NaOH. Place 



both tubes in a water-bath at 40 C. and note rate at which the 

 red colour disappears due to the liberation of fatty acid. This 

 method may be made roughly quantitative by noting the amount 

 of alkali required to neutralise the fatty acid formed. 



FIG. 177. Crystals of leucine and tyrosine. 



CHAPTER X 

 THE BILE. BACTERIAL DIGESTION 



Composition of Human Bile. In I the bile was obtained from the 

 gall bladder : in II the bile was obtained from a fistula. 



100 parts contain i. n. 



Water .... 83 97 



Solids 



Bile salts 



Mucin and bile pigment. 



Cholesterol 



Lecithin and fat . 



Inorganic salts 



17 

 9 

 3 



0-9 

 0-5 

 0-8 



3 



1-0 



0-5 



0-26 



1-2 



0-7-0-8 



