178 



THE MICROSCOPIST. 



This is owing to the rays of light being mostly refracted be- 

 yond the field of vision. On again moistening them, the crys- 

 tals reappear in their octahedral form. Sometimes this salt 



assumes the forms represented at c, more or less resembling 

 dumb-bells.* This forrn ; like the crystals of uric acid, the 



* Dr. Fricke, in the American Journal of Medical Science, July, 

 1850, states as his opinion that the dumb-bell forms of crystals are 

 not oxalate of lime, but disintegrated crystals of uric acid. 



