THE MICROSCOPE. 



13 



is seen by referring to the drawing some of the crystals were very 

 small appearing as a mere point while others were much larger. 

 They are occasionally seen as large as the 3-J-g- of an inch in diam- 

 eter. The urine should be examined for these crystals in a short 

 time after it has left the bladder, for after the lapse of 36 or 48 

 hours they may appear in urine which was devoid of them at first. 

 These crystals very frequently accompany the urates, but as 

 the former are insoluble and the latter soluble in caustic potash they 

 are readily separated. The oxalate crystals, however, are soluble 

 in the mineral acids. 



Crystals of oxalate of lime. Dumb-bell form, x 250. 



The dumb-bell forms are not so common as the others are and 

 they are usually accompanied with the octahedral crystals. 



The "nuclei " of many of the urinury calculi may be demon- 

 strated to consist of these dumb-bell crystals of oxalate of lime. 



HOW TO MOUNT THE STARCHES. 



ANY of the starches are not only very characteristic but they 

 are also very beautiful when viewed by transmitted or polar- 

 ized light. 



We have experimented a great deal to determine, if possible, 



M 



