536 ANIMAL SUBSTANCES 



The pancreatic digestion of food is effected by the following three 

 enzymes which act best in neutral or slightly alkaline solution : 

 (i) Trypsin, which digests proteids. 

 (ii) Amylase (araylopsin), which digests starch by converting it 



into maltose. 



(iii) Lipase (steapsin), which digests fats by converting them into 

 glycerin, and fat-acids, which unite with the alkalies to form 

 soaps. 



Commercial pancreatin is a mixture of these enzymes with other 

 substances. 



ANIMAL SECRETIONS, &c. 



OX GALL 



(Ox Bile, Fel Bovinum) 



Source, &c. Ox gall is the liquid contained in the gall-bladder 

 of the ox, Bos taurus, (Phylum Chordata, Class Mammalia, Order 

 Ungulata). 



The gall-bladder is a pyriform bag attached to the under surface 

 of the liver. It receives the secretion from the liver and discharges 

 it into the duodenum ; this action is continuous, but is increased 

 by the arrival of food in the duodenum. In man the quantity 

 secreted varies from 500 to 1000 c.c. daily. Bile appears to exercise 

 a favourable influence upon pancreatic digestion by increasing the 

 rate of action of the pancreatic enzymes. 



Description. Fresh ox bile is a brownish yellow or brownish 

 green, rather viscous liquid, with an unpleasant odour and disagree- 

 able bitter taste. It is neutral or faintly alkaline in reaction, has a 

 specific gravity of about 1*022. and is characterised by the following 

 reaction : To 10 c.c. of a 5 per cent, aqueous solution of ox bile add 

 a drop of solution of sucrose (I in 4) and then gradually sulphuric acid 

 until the precipitate at first formed is redissolved ; the mixture will 

 acquire a carmine colour changing to violet. This reaction is due 

 to the action of furfuraldehyde (from the sulphuric acid and sucrose) 

 upon cholalic acid (produced by the sulphuric acid acting upon tauro- 

 cholic and glycocholic acids). 



Constituents. -Ox gall contains the sodium salts of taurocholic 

 and glycocholic acids together with colouring substances (bilirubin, 

 biliverdin), mucin, lecithin, cholesterol, fat, soaps, &c., in aqueous 

 solution. For medicinal use the mucin is usually removed by pre- 

 cipitation with alcohol and the filtrate evaporated to a thick extract. 



Uses. Ox gall is given in cases of deficiency of bile, but it is of 

 doubtful medicinal value. 



