288 PHYSICAL CHARACTERS OF BILE. [BOOK II. 



it makes its way into the thoracic duct which carries it into the blood. 

 This fact was proved by applying a ligature to the common bile-duct 

 of dogs, in whose thoracic duct a cannula was inserted permitting the 

 collection externally of the whole of the lymph. Whilst this fluid 

 contained large quantities of the biliary constituents, the blood-serum 

 was entirely free from them. 



Small quantities of undecomposed bile acids are normally present 

 in the chyle of the thoracic duct. Tappeiner was able to isolate and 

 identify them in 150 c.c. of chyle obtained from the thoracic duct of 

 a dog in full digestion 1 . 



SECT. 3. THE PHYSICAL CHARACTERS AND THE REACTION OF 



THE BILE. 



The bile flowing jfrom the hepatic ducts is a non -viscous 

 liquid, the product of the activities of the liver cells. In the 

 gall-bladder, and perhaps even in the cystic and common bile-ducts, 

 it becomes mixed, however, with the product of the secretion of the 

 glands situated in the mucous membrane, and acquires a viscidity, 

 formerly supposed to be due to mucin, but which is caused by a 

 peculiar body now classed among the 'nucleo-albumins' ; we shall 

 designate this body the ' mucoid nucleo- albumin ' of the bile. 



Colour. The perfectly fresh and normal bile of man and of 



carnivorous animals generally (dog, cat, pig) is of a golden red colour. 

 When examined spectroscopically the liquid cuts off more or less of the 

 violet and blue ends of the spectrum ; it either exhibits no definite 

 absorption bands or at most on suitable dilution, a shadowy absorp- 

 tion band near F, occupying approximately the same position as that 

 exhibited by urobilin. 



In the very interesting case of biliary fistula in a woman recorded by 

 Dr Copeman and Mr Winston 2 , the bile presented from first to last *a 

 deep olive tint in which green certainly preponderated over the yellow.' 

 These observations have led Copeman and Winston to surmise that the 

 normal colour of human bile may be olive-green, and that the colour 

 usually described as characteristic of the bile of man may be due to a 

 reducing process occurring during the sojourn of the bile in the gall- 

 bladder. In Jacobsen's description of the bile secreted in Westphalen's 

 case the bile is described as a * grunlich braungelbe Miissigkeit.' 



The fresh bile of herbivorous animals is of a pure grass-green or 

 olive-green colour (rabbit, sheep, goose) or it is of a colour in which 

 green predominates, but in which a red tint is perceptible (ox, some- 

 times sheep). It absorbs the violet and some of the blue rays of 



1 H. Tappeiner, 'Ueber die Aufsaugung der gallensauren Alkalien im Diinndarme,' 

 Sitzungsber. d. Wiener Academic d. Wissensch., Vol. 77 (1878), Abth. in. 



2 S. Monckton Copeman, M.A., M.D., and W. B. Winston, ' Observations on Human 

 Bile obtained from a case of Biliary Fistula,' Journal of Physiology, Vol. x. (1889), 

 213 231, see p. 218 et seq. 



