312 JAUNDICE. ICTERUS. 



even in a state of health, all the bile formed in the liver does 

 not pass into the bile ducts, but that a portion of it enters 

 the hepatic veins, along with the sugar ; the quantity which 

 thus enters, varying with the distribution of the blood in the 

 gland, and with the relative degrees of pressure exerted by the 

 contents of the veins, and of the minute bile ducts upon the 

 secreting cells, being largest, when the pressure on the sides 

 of the veins is least, and when that on the ducts is greatest. 

 The biliary acids which thus enter the blood, or which are 

 re-absorbed from the intestines, are supposed to undergo 

 certain changes from oxydation, and may thus account for the 

 large quantity of taurine which has been found in the healthy 

 lung, and for the pigments which are naturally voided in the 

 urine. When, however, anything interferes with these nor- 

 mal metamorphoses in the blood, as when this fluid becomes 

 contaminated by the purulent infection, or by any other 

 poison, it is supposed, that the complete metamorphosis of the 

 colourless bile into urinary pigments is arrested, and that the 

 intermediate substance-, bile-pigment, is formed in the blood, 

 so as to colour the various tissues and secretions. 



Kiihne has studied this question, and does not believe that 

 the biliary acids are changed in the blood into bile-pigment, 

 but shows that blood-pigment is changed into bile-pigment, 

 under the influence of the biliary acids. By adopting the 

 method of Hoppe, he was able to determine constantly the 

 presence of the biliary acids in the urine of persons suffering 

 from icterus, as well as in that of dogs whose biliary ducts 

 had been tied. When dog's bile, or solution of the biliary 

 acids, was injected into a vein, bile pigment and the salts 

 were detected in the urine. Even in large quantities of 

 healthy urine no biliary acids could be found. 



Symptoms. When jaundice occurs as an idiopathic ma- 

 lady, it is detected by the yellow colour of the visible mucous 



