ABNORMAL INGREDIENTS OF THE URINE. 389 



Potassium ferrocyanide, when introduced into the circulation, ap- 

 pears with great readiness in the urine ; and, according to the observa- 

 tions of Bernard, may begin to be eliminated within twenty minutes 

 after being injected into the duct of the submaxillary gland. 



Iodine, in all its combinations, passes out by the same channel. 

 After the administration, in the healthy human subject, of 192 milli- 

 grammes of iodine, in the form of syrup of the iodide of iron, we have 

 found it to be present in the urine at the end of thirty minutes, and that it 

 continued to be discharged for nearly twenty-four hours. In the case of 

 two patients who had been taking potassium iodide, one of them for six 

 weeks, the other for two months, the urine still contained iodine at the 

 end of three days after the suspension of the medicine ; but at the end 

 of three days and a half it was no longer present. Even when iodine, 

 however, is taken in a free form, as in that of alcoholic solution, it 

 always passes out by the urine in combination. It cannot be detected, 

 accordingly, by the simple admixture of starch with the urine, but must 

 be set free by the addition of a drop or two of nitric acid, after which it 

 produces its characteristic blue color by union with the starch. The 

 same thing is true of the other animal fluids, such as the saliva and the 

 perspiration, by which iodine is also eliminated after its introduction 

 into the system. 



Quinine, when taken as a remedy, has been detected in the urine. 

 Ether passes out of the circulation in the same way, and its odor may 

 sometimes be very perceptible in the urine, after having been inhaled 

 for the purpose of producing anaesthesia. The peculiar odors developed 

 in the urine after the use of Asparagus, and certain other vegetable sub- 

 stances, are produced by a transformation of their ingredients while 

 passing through the animal system. 



Albumen. Under ordinary conditions the albumen of the blood does 

 not pass out in any proportion from the renal vessels ; but whenever the 

 pressure in these vessels is increased beyond a certain point, owing to 

 congestion, compression of the renal veins by abdominal tumors, preg- 

 nancy, or altered nutrition of the kidneys in Bright's disease, the 

 albuminous ingredients of the blood transude through the capillaries 

 and make their appearance in the urine. 



Albuminous urine is usually rather pale, and often somewhat opales- 

 cent from the admixture of exfoliated epithelium cells or of fibrinous 

 casts from the uriniferous tubules of the kidney. When this is the case, 

 it should be rendered transparent by filtration before applying the tests, 

 since the turbidity already existing might mask the reaction, if the 

 albumen were present in small proportion. 



If the urine have an acid reaction, the application of heat produces a 

 turbidity which is more marked in proportion to the quantity of albu- 

 men which it contains In extreme cases the fluid may solidify, like 

 the serum of blood, before reaching the boiling point ; but the albumen 

 is more frequently thrown down in loose whitish flakes. When the 



