282 



Even one of the most recent writers on the urine gives the following 

 description of the physical characters of deposits of phosphate of 

 lime in urine : " Deposits of phosphate of lime," he states, " as 

 usually occurring in the urine, and mixed with magnesia, are always 

 white and amorphous, under the microscope appearing in granules, 

 sometimes of a greenish tinge, which exert a refracting action upon 

 light. Crystallized deposits of this substance have not been ob- 

 served" 



I now propose to show, first, that there is a crystalline deposit, 

 the crystals composing which will be described hereafter, which does 

 really consist of phosphate of lime ; second, that it is of frequent 

 occurrence in human urine ; and third, that it is of greater patho- 

 logical importance than the deposits of triple phosphate. 



I would first remark that I have for years been acquainted with 

 the fact of the occurrence of crystalline phosphate of lime in the 

 urine, and I have referred to it in ' The Lancet' of 1853, and also 

 elsewhere. I should now remark, however, that the statement made 

 by me as to the composition of the crystals, has hitherto been based 

 upon their qualitative analysis only, and therefore was not so com- 

 pletely conclusive and satisfactory as could be desired. Until 

 recently I had not made any quantitative analyses ; these I have 

 since been enabled to perform, and I now furnish the results of the 

 chemical examination of four samples of the deposit. 



First Sample. Filtered from the urine of twenty-four hours ; 

 mixed, as ascertained in the first instance by means of the microscope, 

 with a very minute quantity of triple phosphate. 



Bibasic phosphate of magnesia 0*15 



Bibasic phosphate of lime T85 



2-00 



Second Sample. Filtered from urine after the lapse of a day or 

 two ; mixed with a small quantity of triple phosphate. 



Bibasic phosphate of magnesia 0*47 



Bibasic phosphate of lime 6' 18 



6-65 

 Third Sample. From urine of twenty-four hours, after the lapse 



