178 THE DIGESTIVE FLUIDS. 



line form, and can be further purified by recrystallization from a 

 mixture of alcohol and ether. 



Other Organic Constituents of the Bile. In addition to the 

 bodies already described, the bile contains small amounts of 

 lecithin, of palmitin, stearin, olein, and the soaps of the correspond- 

 ing fatty acids. In ox-bile Lassar-Cohn found also traces of 

 myristinic acid, C U H 28 O 21 , which has heretofore only been observed 

 in the spermaceti of whales. We further find traces of urea, 

 and occasionally a diastatic ferment, which is by some observers 

 regarded as identical with ptyalin. Its presence, however, is by 

 no means constant, and it can scarcely be regarded as playing a 

 role in the process of intestinal digestion. Larger amounts of urea, 

 according to Hammarsten, are found in the bile of the shark and 

 the sturgeon. 



In decomposing bile cholin, glycerin-phosphoric acid and tri- 

 methylamin may be observed, and are referable to the decomposition 

 of lecithin. 



The Biliary Iron. 



If we recall the origin of bilirubin from hsematin, we should 

 expect to find in the bile the iron which is liberated during the 

 decomposition of the latter. Traces of iron, indeed, are constantly 

 present, principally in combination with phosphoric acid. The 

 amount, however, which is thus eliminated is far too small to repre- 

 sent that which must of necessity be set free. Kunkel thus found 

 that while 100 parts of hsematin correspond to 9 parts of iron, only 

 1.4-1.5 parts of iron appear in the urine for every 100 parts of 

 bilirubin. But even if we add to this the amount which is eliminated 

 in the urine and that which is excreted through the intestinal mucosa, 

 we still find a very large deficit, and we are accordingly forced to 

 the conclusion that the greater portion of the iron must be retained 

 in the liver. But while such a retention must of necessity occur, we 

 are ignorant of the manner in which it is accomplished. Of the 

 form, also, in which the iron exists in the liver we know but 

 little. That it is subsequently utilized in the construction of hsemo- 

 'globin is quite likely, but not proved. Naunyn and Minkovvski have 

 observed that following poisoning with arseniuretted hydrogen, iron- 

 containing pigments can be demonstrated in the liver. Latschen- 

 berger speaks of the formation of choleglobins as antecedents of bili- 

 rubin, and of the simultaneous appearance of iron-containing melanins 

 in the liver; and Neumann has demonstrated the presence of an 

 organic iron pigment, haemosiderin, in old extravasations of blood 

 and in thrombi together with hsematoidin ; but of the true nature 

 of these substances we practically know nothing. It is possible 

 that the globin, which must of necessity be liberated during the 

 decomposition of hsematin, takes up the iron which is set free from 

 the latter ; but this also is a supposition, and further researches in 

 this direction are needed. 



