262 EXCRETION. 



Robin, 1 that all of these contain water entering into the 

 composition of their coagulable principles ; so that their pro- 

 portion of water, as it is ordinarily given, is really not greater 

 than in the bile. Among the inorganic salts, we find chloride 

 of sodium in considerable quantity, and a large proportion of 

 phosphates. "We also note the presence of salts of iron, of 

 manganese, and a small proportion of silicic acid. 2 



The fatty and saponaceous matters demand hardly any 

 more extended consideration. A small quantity of margarine 

 and oleine are held in solution, partly by the small propor- 

 tion of soaps, but chiefly by the taurocholate of soda. These 

 principles sometimes exist in larger quantity, and may be 

 discovered in the form of globules. The proportion of soaps 

 is very small. Lecithene, a phosphorized fat, is mentioned by 

 Robin and others, but its constitution is not definitely set- 

 tled. All that is known of this principle is that it is a 

 neutral fatty substance extracted from the bile, and is capa- 

 ble of being decomposed into phosphoric acid and glycerine. 

 Choline (C 10 H 13 NO 2 ) is a peculiar alkaloid found in the bile 

 in exceedingly minute quantity. 



Biliary Salts. 



The principles which we have called biliary salts are 

 compounds of soda with peculiar organic acids, found no- 

 where but in the liver, and undoubtedly produced in this 

 organ from materials furnished by the blood. The fact that 

 the bile possesses peculiar principles has long been recog- 

 nized. It is unnecessary, however, to follow out in detail 

 the earlier chemical investigations into their properties ; for 

 the biliary matter of Berzelius and the picromel and biliary 

 resin of Thenard are now known to be composed of sev- 

 eral distinct proximate principles. Our exact knowledge 



1 ROBIN, Legons sur les humeurs, Paris, 1867, p. 543. 



2 The presence of hydrochlorate of ammonia and the ammonio-magnesian 

 phosphate has lately been indicated in the bile by M. Bergeret (de Saint-Leger). 

 Journal de Vanatomie, Paris, 1869, tome vi., p. 437. 



