562 
MECHANISM OF BILE SECRETIOX. 
In cases of occluded gall bladder this mucin-like substance has been 
found to be the chief organic solid of the secretion. 1 
Mayo Robson , s Analysis. 
Organic matter, chiefly mucin . . . -672 per cent. 
Chlorides equal to NaCl .... '573 ,, 
Sodium carbonate ..... "220 „ 
Other salts containing phosphates, potassium 
salts, etc. ...... "071 ,, 
The fact that the amount of this substance does not vary with the 
true bile constituents either at different periods of the day, 2 or in febrile 
conditions, 3 indicates very clearly that it is not formed by the liver 
cells. 
Salts of the bile acids.— These are entirely produced in the liver 
cells. In Birch and Spong's case, and in the case examined 1 iy Mayo 
Eobson, they were entirely absent from the secretion of the gall 
bladder. 
That they are actually formed by the liver cells, and not merely ex- 
tracted from the blood, was demonstrated by Minkowski and Xaunyn. 4 
These observers found that, while bile salts are normally absent from the 
blood, they appear when the bile duct is ligatured. If, however, the 
liver be excluded from the circulation, there is no accumulation of bile 
salts in the blood. 
The source of the cholalic acid moiety of the glycocholic and 
taurocholic acids is unknown. The source of the glycine and taurine is 
to be sought ultimately in the proteids of the body and of the food, 
since these alone can yield the nitrogen and sulphur. Both are amido- 
acids of the fatty acid series. 
Xencki, Pawlow and Zaleski, 5 have shown that the surplus proteid 
of the diet is largely broken down into ammonia compounds in the wall 
of the intestine, and these compounds pass to the liver. Yon Schroder 6 
demonstrated that ammonia compounds are readily converted to urea by 
the liver. Hence by far the greater quantity of nitrogen in excess of 
that required must undergo this transformation, and it is not to be 
expected that an additional quantity of proteids in the food will lead to 
a markedly increased formation of bile acids. Spiro, 7 by feeding animals 
with biliary fistuke upon various kinds of food, found that a proteid diet 
increased the nitrogen and sulphur excreted in the bile, but not in 
proportion to the amount of proteid taken. 
The following figures illustrate Spiro's results : — 
Food. 
Sulphur of Bile 
in Grms. 
Xitiogen of Bile 
in Gnns. 
Fasting .... 
125 grms. flesh . 
500 ,, ... 
919 ,, ... 
•059 
•089 
•155 
•173 
•195 
•292 
•398 
•604 
1 Hoppe-Seyler, "Physiol. Chem.," S. 302. 
- Bep. Lab. Roy. Coll. Phys., Edinburgh, vol. iii. p. 204. 
3 Ibid. p. 212. 4 Arch.f. exper. Path. u. Pharmakol., Leipzig, Bd. xxi. S. 
5 Ibid.. Bd. xxxvi. S. 26. 
6 Ztschr. f. physiol. Chem., Strassburg, Bd. ii. S. 234. 
7 Arch.f. Physiol., Leipzig, 18S0, Supp. Bd. S. 50. 
