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 1 found, after 
giving sodium glycocholate for three days (5-9 grms. 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. Maly and Emich state that 
taurocholic acid completely precipitates native proteids, but not albuni- 
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. Wissensch., Berlin, 1885, Bd. xxiii. S. 121. Similar results have 
been obtained by Prevost and Binet, Coirvpt. rend. Acad. d. sc, Paris, 1888, tome cvi. p. 
1690 ; Winteler, Iriaug. Diss., Dorpat, 1892. 
2 Kunkel, Arch. f. d. ges. Physiol., Bonn, 1877, Bd. xiv. S. 344 ; Spiro, Arch. f. Ana/, 
it. J'/n/sio/., Leipzig, 1880, Supp. Bd. S. 50. 
3 Sitzungsb. <l. /.'. Akad. d. JJ'issensch., Wien, 1878, Bd. lxxrii. Abth. 3. 
4 " Die Verdauungssafte," 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. u. d. Fortschr. d. ges. Med., Erlangen, 1870, Bd. 1, S. 106. See also 
Chittenden and Cummins, Am. Ohe/m. Journ., Baltimore. 1885, vol. vii. p. 36; Jahresb. 
ii. d. Fortschr. d. Thier-C'hem., Wiesbaden, 1885, Bd. xv. S. 319. 
