164 A. PoLiCARD, C. A. Baud, A. Collett, H. Daniel-Moussard, J. C. Martin 



cells, often polymorphonuclear leukocytes. The clusters of needle-shaped crystals are 

 separated from the cytoplasm by a vacuole limited by a single cytomembrane. 



The ultrathin sections of the material embedded in methacrylate give an electron 

 diffraction pattern which is to be interpreted as a mixture of hydrated acid calcium 



nd 15 davs without injecti 



orthophosphate or brushite and hydrated calcium metaphosphate (d-=4.26, 4.10, 

 3.68, 2.96, 2.93, 2.48, 2.45, 2.37, 2.19, 2.08, 1.87). 



By extraction with boiling glycerine and potassium hydroxide according to 

 Gabriel, a mineral fraction is obtained which diffracts X-rays like apatite. There 

 is no disagreement with the result from electron diffraction, since synthetic brushite 



