462 Veterinary Medicine. 



The coloration of the tissues may be a simple tinge of yellow 

 especially noticeable in the eye (conjunctiva;, or it may amount 

 to the darkest shades of orange and brown. It may or may 

 not be complicated by the presence of spots or patches of blood- 

 staining (ecchymosis) on the visible mucous membranes but 

 especially' in cases con)plicated by poisoning with taurocholic acid 

 or effete nitrogenous products. 



The urine may be similarly colored in all shades of yellow or 

 orange brown, and may leave a correspondingly deep .stain on 

 white paper. 



The test for bile pigments (Gmelin's) is simple and beautiful. 

 Pour a little nitric acid into a test tube held obliquelj- and then 

 add a few drops of sulphuric acid, and finally a little urine, so 

 slowly, that it will remain on the surface. Soon at the point of 

 junction appear in succession the various colors of the rainbow : 

 yellow, green, blue, violet, red and lastly a dirty yellow. It is 

 open to this objection that the characteristic play of colors may 

 be produced by alcohol in the absence of bile pigments. Indican 

 also will produce the green and yellow with blue between but 

 never the violet nor red, nor all in their regular order. 



A second iJiode of applying this test is by spreading a few drops 

 of the urine on a white plate and letting fall a drop of nitric acid 

 in the centre. The play of colors is very characteri.stic. 



^\\Q test for bile acids ( Pettenkofer's) is to place a portion of 

 the urine in a test tube, and after adding a drop of syrup, to add 

 cautiously, drop by drop, two-thirds of the amount of sulphuric 

 acid. Shake the mixture and set aside for some minutes. If 

 suflBcient heat is not produced by the mixing of the acid and 

 urine warm slightly. The mixture becomes of a dark violet 

 color which is destroyed by a temperature a little above 140° Fall. 



A convenient application of this test (Stranburg) is to add a 

 little cane sugar to the urine, dip a piece of filtering paper in the 

 mixture, dry it tlKnoughly, pour a drop of sulphuric acid on the 

 paper and allow it to run partially off. In a quarter of a minute 

 a beautiful violet color is produced, best seen by holding up the 

 paper to the light and looking through it (Brunton). 



In cases due to obstruction of the bile ducts the dung is desti- 

 tute of bile, whitish, often clayey and foetid, while in cases due 

 to reabsorption without obstruction the faeces have their natural 

 color and odor. 



