190 THE URINE. 



sediment, if it contains epithelial cells, is often colored 

 brown. Upon shaking the urine the foam is yellow or 

 greenish. 



A common cause for the appearance of the biliary 

 constituents in the urine is the obstruction of the bile- 

 duct. This may be either from some abnormal growth 

 or merely from inflammation in the passages. The bile 

 is then absorbed by the lymphatics and excreted through 

 the kidneys. The same result may be produced by any 

 abnormal condition of the liver which interferes with the 

 free passage of the bile. A part of the bile may pass from 

 the blood into the tissues, manifesting itself there by its 

 characteristic color (icterus). 



The biliary coloring matters may be formed in the liver, but 

 they can also be produced by the decomposition of the haemo- 

 globin in the blood and the other tissues of the body, and may 

 pass from here directly into the urine. In this case the urine 

 would contain none of the biliary acids, since they do not appear 

 to be formed outside the liver. A large amount of these acids 

 with the pigments in the urine indicates that the bile comes from 

 the liver (hepatogenous icterus). Some authors have described as 

 a distinct form of icterus that in which the biliary pigments ure de 

 rived from the blood-coloring matters (haematogenous icterus). It 

 seems, however, to be certain that the biliary acids may be absent 

 from the urine even when it contains bile from the liver or gall- 

 bladder. 



397. THE PRODUCTION OF ARTIFICIAL JAUNDICE. Insert a 

 small cannula into the common bile duct of an anaesthetized 

 albino rabbit. Allow a dilute solution of indigo carmine to flow 

 into this from a burette. The conditions are similar to those 

 where the bile is reabsorbed in consequence of some obstruction in 

 the common duct. In a few minutes the mucous membranes show 

 the blue color and it soon is seen under the skin in all parts of the 

 body. Make an autopsy, examining the internal organs to learn 

 how extensive is the diffusion of the color through the tissues. 



