URINE. 339 



The best test for its presence is the iodated iodide of potassium, 

 consisting of four parts of iodide of potassium, one of iodine, 

 and ten of water. The precipitate afforded by this reagent 

 with disulphate of quinine is very insoluble in water, not 

 affected by an excess of the test, and readily soluble in alcohol. 

 It is of a yellowish-brown colour, and forms a turbidity or sedi- 

 ment, according to the amount of the alkaloid in the urine. 

 When the quantity is very small there is merely an olive tint 

 produced on the addition of the test. The disulphate of quinine 

 may be reobtained from the sediment in a state of purity by 

 a simple chemical process. 1 



Morphia is stated to have been once detected by Barruel in 

 the urine of a person under the influence of a poisonous dose 

 of laudanum, and it was likewise discovered by Orfila, in the 

 urine of dogs. None of the other alkaloids have yet been de- 

 tected in the urine. 



Indifferent organic substances. According to Wohler, most 

 colouring matters and many odorous principles passed unchanged 

 or slightly mocfified into the urine. In the former class we 

 may place indigo, gamboge, rhubarb, red beet-root, madder, 

 logwood, mulberries, black cherries, &c. ; in the latter, valerian, 

 asafoetida, garlic, castoreum, saffron, turpentine, &c. 



Alcohol is placed by Wohler amongst the substances that 

 do not enter the urine, and Liebig has recently affirmed that 

 it has never been found in that secretion. It has, however, 

 been detected by Percy in the urine of a dog, into whose sto- 

 mach four ounces of spirit of *85 had been injected, and in the 

 urine of a man in a state of intoxication who had taken about 

 a bottle of whiskey. In both cases he obtained, by careful 

 distillation, an inflammable fluid that dissolved camphor. 2 



In order to ascertain whether alcohol, taken in moderate 

 quantity would enter the urine, my friend Dr. Wright instituted 

 the following experiment on a man whose ureters opened ex- 

 ternally. Three ounces of whiskey were administered, and the 

 urine collected by applying a test-tube to each ureter. The 

 tubes were corked and replaced every two minutes, for the 

 space of half an hour. 



1 Journal de Pharmacie, Sept. 1843. 



8 On the presence of Alcohol in the Brain, 1839, p. 104. 



