394 Scientific Intelligence. [Nov. 



XIX. Urinary Concretion on a Leaden Pipe. 



In the Glasgow Infirmary, there is a lead pipe about three 

 inches in diameter, through which all the urine collected in the 

 hospital has been discharged for upwards of 20 years. The 

 inside of the pipe was encrusted with a matter, somewhat 

 similar to calc tuff, and above an inch thick. I had the curiosity 

 to examine this substance in order to ascertain its compo- 

 sition. 



Twenty-five grains of it were reduced to a coarse powder, and 

 boiled for two hours in distilled water. The liquid was then 

 passed through a filter, and the undissolved matter dried at the 

 temperature of 212°. It weighed 107 gr. and had exactly the 

 same appearance as at first. 



The water being evaporated left one gr. of a brown coloured 

 matter, which, when exposed to a heat of 212°, gave out traces 

 of ammonia, and became insoluble in water. Nitric acid readily 

 dissolved it, and converted it into bitter ; but I could obtain no 

 traces of oxalic acid. The soluble portion of course contained 

 urea. The greater part of this matter had been decomposed by 

 the boiling. Hence the loss of weight sustained. 



The 19'7 gr. were dissolved in muriatic acid. There remained 

 undissolved 1*1 gr. of matter, chiefly siliceous sand, but contain- 

 ing also a brown substance, which dissolved with effervescence 

 in nitric acid, becoming yellow and gelatinous. Probably, there- 

 fore, it was albumen. 



The muriatic acid solution, being precipitated by ammonia, 

 let fall 5*8 gr. of phosphate of lime. Carbonate of ammonia 

 afterwards threw down 2*8 gr. of carbonate of lime. 



The matter deposited in the lead pipe dissolved with efferves- 

 cence in muriatic acid, and, therefore, contained carbonate of 

 lime. 



Thus the 25 gr. of the incrustation yielded the following 

 substances : 



\ ,, ea ' Sec. 1-0 



Albumen and sand r 1 



Phosphate of lime 5-8 



Carbonate of lime 2-8 



10-7 



o m :■ 



I believe 4 - 3 gr. of urea to have been decomposed during the 

 analysis ; so that the deficiency amounts to 10 gr. Probably the 

 greatest part of this is water. It is very remarkable that I could 

 detect no soluble saline matter in this incrustation. 



This analysis seems to prove that carbonate of lime is one of 

 the constituents of human urine. 



