392 CHEMISTRY OF THE DIGESTIVE PROCESSES. 



cholalic acid be given by the mouth, the amount of bile is increased, but 

 still only taurocholates are found in the bile ; but Weiss l found, after 

 giving sodium glycocholate for three days (5-9 grins, per diem), that 

 the bile in the gall bladder at death contained glycocholates, amounting 

 to 25-30 per cent, of the total bile salts present. 



3. No connection exists between the amount of proteid metabolism 

 and the amount of cholates produced, such as would be found if the 

 cholates were a channel for the excretion of the nitrogen and sulphur of 

 proteid decomposition products. 2 



4. Tappeiner 3 identified bile salts in chyle obtained from the 

 thoracic duct in the dog. 



5. Bidder and Schmidt 4 only found cholalic acid in traces in the faeces. 

 A review of all these facts shows that the bile salts are not an 



excretion, but perform a circulation in the body. Besides the function 

 of dissolving the cholesterin to be excreted, the bile salts are also 

 credited with the effect produced by bile in aiding the absorption of 

 fats. 5 Again, bile salts dissolve insoluble soaps of the alkaline earths. 

 This may be shown by precipitating a soluble soap with calcium or 

 magnesium sulphate, and then adding a solution of bile salts and gently 

 warming when the precipitate dissolves. 6 Maly and Emich state that 

 taurocholic acid completely precipitates native proteids, but not album- 

 oses or peptones. 7 This in part explains the precipitation observed when 

 a solution in which peptic digestion is going on (or gastric chyme) is 

 mixed with bile; but part of the precipitate is doubtless mucin from 

 the bile itself. The subject has been investigated by Hammarsten, 8 

 who found that syntonin was completely, peptone only partially, pre- 

 cipitated from an acid solution in which peptic digestion of hard-boiled 

 white of egg had been carried out, by the addition of bile from which 

 the mucin had been removed by alcohol. Hammarsten supposes that 

 the purpose of this precipitation of the semi-digested proteid, which 

 must occur in natural digestion when the gastric chyme comes in 

 contact with the bile, is that it may, by adhering to the intestinal wall, 

 be longer subjected to intestinal digestion than it would be if it remained 

 in solution. 



1 Centralbl.f. d. med. WissenscJi., Berlin, 1885, Bd. xxiii. S. 121. Similar results have 

 been obtained by Prevost and Binet, Compt. rend. Acad. d. sc., Paris, 1888, tome cvi. p. 

 1690 ; Winteler, Inaug. Diss., Dorpat, 1892. 



2 Kunkel, Arch. f. d. ges. PhysioL, Bonn, 1877, Bd. xiv. S. 344 ; Spiro, Arch. f. Anat. 

 u. PhysioL, Leipzig^ 1880, Supp. Bd. S. 50. 



3 Sitzungsb. d. Jo. Akad. d. Wissensch., Wien, 1878, Bd. Ixxvii. Abth. 3. 



4 " Die Verdauungssiifte," S. 217. 5 Vide " Fat Absorption," p. 454. 



6 Neumeister, " Lehrbuch d. physiol. Chem.," Jena, 1893. 



7 Monatsh.f. Chem., Wien, 1883, Bd. iv. S. 89 ; 1885, Bd. vi. S. 95. 



8 Jahresb. it. d. Fortschr. d. ges. Med., Erlangen, 1870, Bd. 1, S. 106. See also 

 Chittenden and Cummins, Am. Chem. Journ., Baltimore. 1885, vol. vii. p. 36 ; Jahresb. 

 ii. d. Fortschr. d. Thier-Chem., Wiesbaden, 1885, Bd. xv. S. 319. 



