iQ2 TEXT-BOOK OF PHYSIOLOGY. 



the color varies. In the herbivorous animals it is usually green; in the car- 

 nivorous animals it is orange or brown. In man it is green or a golden 

 yellow. The colors are due to the presence of pigments. Microscopic 

 examination fails to show the presence of structural elements. 



Human bile obtained from an accidental biliary fistula was shown by 

 Jacobson to contain the following ingredients, viz. : 



COMPOSITION OF HUMAN BILE. 



Water 977 .40 



Sodium glycocholate 9-94 



Sodium taurocholate a trace 



Cholesterin o . 54 



Free fat o . 10 



Sodium palmitate and stearate 1 .36 



Lecithin o .04 



Organic matter, and pigments bilirubin and biliverdin 2 .26 



Sodium chlorid 5 .45 



Potassium chlorid o . 28 



Sodium phosphate i .33 



Calcium phosphate o .37 



Sodium carbonate o . 93 



1000.00 



In this analysis the solid ingredients constitute 22.6 parts per 1000, of which 

 two-thirds are organic and one-third inorganic. The amount of solid varies 

 according to the animal from which the bile is obtained. 



Sodium Glycocholate and Taurocholate. Of the various ingredients 

 of the bile none are more important than these two salts, usually known as 

 the bile salts. The sodium glycocholate is found most abundantly in the 

 bile of herbivora, the sodium taurocholate in the bile of the carnivora. These 

 salts are compounds of sodium and glycocholic and taurocholic acids. 

 When separated from the sodium, the acids will crystallize in the form of 

 fine acicular needles. Under the influence of hydrating agents, such as 

 dilute acids and alkalies, both acids will undergo cleavage into their re- 

 spective components e.g., glycocoll and cholalic acid, taurine and cholalic 

 acid. Glycocoll and taurine are crystallizable nitrogenized compounds 

 known chemically as amido-acetic and amido-isethionic acids respectively. 

 The bile salts are produced in the liver by a true act of secretion, as they 

 are not found in any of the tissues and fluids of the body. After being dis- 

 charged into the intestine they undergo chemic changes, after which they 

 can no longer be recognized. In all probability they are resorbed into the 

 blood and play some ulterior part in the nutrition of the body. 



The presence of the bile salts can be demonstrated by the employment 

 of Pettenkofer's test or reaction. It was shown by this investigator that if 

 to a solution of bile salts a small quantity of a 10 per cent, solution of cane- 

 sugar be added and subsequently a small quantity of strong sulphuric acid, 

 a brilliant red color appears which soon passes into a rich purple. To 

 secure the best results in the performance of this test care should be exercised 

 to keep the temperature below 70 C.; the characteristic colors appear to 

 be due to the action of the sulphuric acid on the cane-sugar by which a 

 substance, furfurol, is produced, which in turn reacts with the cholalic acid. 

 This test can be applied to bile directly; thus if to bile in a test-tube cane- 

 sugar be added and the mixture thoroughly shaken, a portion of the bile 



