100 HUMAN PHYSIOLOGY. 



reasons it is believed that here also these bodies are preceded in their 

 development by proteoses, of which there is probably but one form, viz., 

 secondary proteoses. Long-continued action of the pancreatic juice, as 

 previously stated, decomposes the peptone into leucin, tyrosin, etc. 

 3. Upon fats. The most striking action of the pancreatic juice is the cleavage 

 of the neutral fats into a fat acid and glycerine with an accompanying 

 emulsification of the remaining neutral fat. 



When pancreatic juice comes into relation with neutral fats they at once 

 combine with water after which they undergo a cleavage into a fat acid, 

 oleic, palmitic and stearic and glycerin. The fat acids then combine 

 with alkalies and form soaps. Coincident with this a portion of the fat 

 is finally divided and held in suspension in the soap forming an emulsion. 

 This emulsified fat subsequently also undergoes the customary cleavage 

 into fat acids and glycerin. This is accomplished by the enzyme steapsin. 



The bile has an important function in the elaboration of the food and in 

 its preparation for absorption. It is a golden-brown, viscid fluid, having a 

 neutral or alkaline reaction and a specific gravity of 1020. 



COMPOSITION OF BILE. 



Water 859 .2 



Sodium glycocholate 1 

 Sodium taurocholate / 



Fat 9.2 



Cholesterin 2.6 



Mucus and coloring-matter 29 .8 



Salts 7.8 



The biliary salts, sodium glycocholate and taurocholate, are characteristic 

 ingredients, and by the process of secretion are formed in the liver from 

 materials furnished by the blood. It is probable that they are derived from 

 the nitrogenized compounds, though the stages in the process are unknown. 

 They are reabsorbed from the small intestine to play some ulterior part in 

 nutrition. 



Cholesterin is a product of waste taken up by the blood from the nerve 

 tissues and excreted by the liver. It crystallizes in the form of rhombic plates 

 which are quite transparent. When retained within the blood, it gives rise 

 to the condition of cholesteremia, attended with severe nervous symptoms. 

 It is given off in the feces under the form of stercorin. 



