284 



analyses, therefore, show that the crystallized phosphate of lime is a 

 tribasic phosphate containing two atoms of lime, and most probably 

 one of water. 



Form of the Crystals. 



The size, form, and arrangement of the crystals of phosphate of 

 lime, as they occur in human urine, vary greatly, but the peculiarities 

 are in all cases sufficiently characteristic to allow of the ready iden- 

 tification of this phosphate by means of the microscope. The 

 crystals are either single or aggregated, most frequently the latter, 

 forming glomeruli or rosettes, more or less perfect (figs. 1, 2, 3). 

 Sometimes they are small and needle-like, and then they frequently 

 form by their crossing and union at right angles, glomeruli or sphe- 

 rules (fig. 3). Sometimes the crystals are thin and flat, having oblique 

 Fig. 1. Fig. 2. 



Fig. 3. 



Fig. 4. 



or pointed terminations (fig. 2). Very frequently, however, they 

 are thick, and more or less wedge-shaped, and united by their narrow 

 extremities so as to form more or less complete portions of a circle 

 (fig. 1) ; the free larger ends of the crystals are usually somewhat 

 oblique, and the more perfect crystals present a six-sided facette. I 

 have never yet met with these crystals having both ends perfect, owing, 

 I believe, to the tendency which they have to crystallize from a centre 



