i64 THE MICROSCOPE. 



THE PREPARATION OF CRYSTALS. 



BY A. Y. MOORE, CLEVELAND, OHIO. 



MANY salts can be crystallized from their solution upon a slide 

 and mounted dry or in Canada balsam; but, in many cases, it 

 will be found that the crystals gradually become altered. They 

 become less brilliant, or sometimes completely dissolve. 



For some time past I have resorted to a method, which — so far 

 as I am informed — is new. In brief it is this : 



A cell is made upon an ordinary slide with some cement upon 

 which the salt solution has no solvent action. A cold, saturated 

 solution is then made of the salt solution desired. The solution is 

 then heated, so that it will dissolve still more of the salt. 



The cell should then be filled with the warm solution and im- 

 mediately sealed. Upon cooling the crystals will be deposited 

 within the cell in a most beautiful manner, and their lustre is re- 

 tained. 



While filling and sealing the cell, the slide may be kept warm 

 by placing it upon the turn table which has been previously heated, 

 but care is required not to overheat it, which would soften the ceil 

 or cause an evaporation of the liquid. 



Glycerine is an excellent medium for such salts as it will dis- 

 solve, and is easily sealed. I use quick-drying gold size as a cement 

 for sealing such preparations, as it hardens quickly and holds well. 



THE MICROSCOPE AMONG INFINITIES. 



BY J. M. ADAMS. 



IT is a question already brought up by those who make a specialty 

 of the minutest forms of life, whether the microscope will be able 

 to reveal them sulificiently to distinguish one from the other, inde- 

 pendent of their effects. 



The minute species of micrococci., being mere points, but which 

 infuse the serous fluids in many diseases, although they are specifi- 

 cally different, as they produce certain identical and specific 

 changes and effects, yet cannot be well distinguished from each 

 other until the symptoms of the disease appear. 



Many of the smaller bacterian forms differentiate to such a 

 minute line or dot, that they fade out of sight, but from comparisons 



