ANALYSIS OF THE URINE. 



345 



cular pressure in the liver (chronic affections of the heart with 

 lowering of the arterial pressure). The activity of the biliary secre- 

 tion being regulated by the vis à tergo of the arterial blood, when 

 the blood pressure is lowered (in intense pain, for instance), the bile 

 is subjected to a true resorption and passes into the blood. 



4. Intestinal catarrhs of the dog. This cause explains the fre- 

 quency of the appearance of the coloring matters of the bile in the 

 dog's urine. Here the pathology of hemoglobinuria is complex. 

 There exists sometimes an inflammatory obstruction of the ductus 

 choledochus; in other cases the diarrhea does not give the coloring 

 matters of the bile time to become decomposed as in the normal 

 state ; they may thus pass as they are from the intestine into the 

 blood, to be eliminated with the urine. (When normal they are 

 transformed into hydrobilirubin or urobilin, and are eliminated in 

 the shape of coloring matters found in the urine.) 



5. Certain alterations of the blood, which seem to be able to 

 create the coloring matters of the bile at the expense of the hemo- 

 globin (hematogenic icterus). 



The biliary acids, contrary to coloring matters, constitute ele- 

 ments of the normal composition of the urine ; they are found in 

 quite large quantity in cholemia and choluria ; these are cardiac 

 poisons (reduction of the pulse in icterus). Every urine gives a 

 weak reaction of gallic acid (Pettenkofer's test) — that is to say, a 

 purple coloration when treated with cane sugar or concentrated 

 sulphuric acid. 



Tests for coloring matters of the bile in the urine. 1. By means 

 of Gmelin's reaction, dilute fuming nitric acid gives successively 

 the following characteristic colors : green, yellow, red, violet, blue. 

 2. According to Briick, the same combination of colors is obtained 

 by adding pure nitric acid and sulphuric acid. 3. In adding a 

 concentrated solution of Chilean nitrate we see again the same color 

 transformations (Fleiscbl). According to Latschenberger, it is diffi- 

 cult to demonstrate the coloring matters of the bile in the urine of 

 the horse. This author advises to dilute the urine with water, then 

 to add a solution of baryta and let it rest from twelve to twenty- 

 four hours, decant, and finally submit the precipitate to Gmelin's 

 test. 



IV. Grape sugar. The transient existence of this sugar in 

 urine is called glycosuria or mellituria; this condition when per- 

 sistent and chronic bears the name of sugar diabetes (diabetes mel- 



