THE TJRIXE. 335 



After the administration, in man, of 192 milligrammes of iodine, in 

 the form of syrup of the iodide of iron, we have found it in the urine 

 at the end of thirty minutes ; its elimination continuing for nearly 

 twenty-four hours. In two patients who had been taking potassium 

 iodide one for six weeks, the other for two months the urine still con- 

 tained iodine three days after the last dose ; but at the end of three 

 days and a half it was no longer present. Iodine, as discharged by 

 the urine, is always in the form of combination, from which it must 

 be set free by the addition of a drop of nitric acid, after which it pro- 

 duces its characteristic blue color by admixture with starch. The same 

 is true of other animal fluids, such as saliva and the perspiration, by 

 which iodine is also eliminated after its introduction into the system. 



Quinine, when administered as a remedy, has been detected in the 

 urine. Ether passes out of the circulation in the same way, and its 

 odor is sometimes perceptible in the urine, after being inhaled for the 

 production of anaesthesia. The peculiar odors developed in the urine 

 after the use of Asparagus, and certain other vegetable substances, 

 are produced by a transformation of their ingredients while passing 

 through the system. 



Albumen. Under ordinary conditions the albumen of the blood does 

 not pass out from the renal vessels; but when the local pressure is 

 increased beyond a certain point, owing to congestion, compression of 

 the renal veins by abdominal tumors, pregnancy, 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 pale, and often opalescent from the 

 admixture of exfoliated epithelium cells or of fibrinous casts from the 

 uriniferous tubules. In these cases, it should be rendered transparent 

 by filtration before applying the tests, since the turbidity already exist- 

 ing might mask the reaction of albumen, if present in small proportion. 



In albuminous urine with an acid reaction, the application of heat 

 produces a turbidity which is in proportion to the quantity of albumen 

 present, In extreme cases it may solidify, like the serum of blood, 

 before reaching the boiling point ; but more frequently the albumen is 

 thrown down in loose whitish flakes. When the turbidity produced by 

 boiling is moderate in amount, it may resemble that due to precipitation 

 of the earthy phosphates. It can, however, be distinguished by the 

 addition of a drop of free acid, which at once redissolves the phosphates, 

 but does not affect a turbidity caused by albumen. An albuminous 

 precipitate, on the other hand, however abundant, is redissolved by the 

 addition of a caustic alkali. 



If the urine be alkaline in reaction, boiling may not throw down its 

 albumen, this substance being soluble in an alkali. Alkaline urine, 

 accordingly, if suspected of being albuminous, should be rendered dis- 

 tinctly acid before boiling, by the addition of a small quantity of a free 

 acid. 



Xitric acid, added in moderate quantity to albuminous urine, produces 



