44 THE MICROSCOPE. Mar., 



If you want the best, pay SIO for Sternberg's Bacteriology. 

 If only the rudiments, we can get you Ball's Essentials of Bac- 

 teriology for about $1.25 postpaid, or for $2.25 we can order 

 Reeves' Medical Microscopy which contains colored illustra- 

 tions of Bacteria with descriptions and will besides give you 

 lots of information about urinalysis, the blood, etc. — C. W. S. 



222. Iiiyish to use mounted specimens and 'project the image through 

 a microscope upon a screen. — Can I use a lamp or gas light for illu- 

 mination f — IF. F. Proschwitzky . 



You will require an oxy-hydrogen lime light or a small elec- 

 trical arc light. The pencil of light must be small enough to 

 pass through the small lenses of the objective and bright enough 

 to bear the subsequent spreading out upon the screen. 



PRACTICAL SUGGESTIONS. 



By L. A. WILLSON, 



CLEVELAND, OHIO. 



The Mounting of Sponge Spicules. — First place a drop 

 of balsam on the center of the slide. Then sprinkle some 

 spicules over the drop and cover with a thin glass. Then heat 

 and boil until all bubbles disappear. Set away to cool and a 

 good slide will be the result. The large spicules may be 

 arranged and mounted as opaque objects and will thus make 

 very beautiful slides. 



Cleaning and Dismounting Slides and Covers. — Heat 

 the slide with the cover over a lamp until the cover moves. 

 Then remove the cover ; soak cover and glass slip in turpentine. 

 A drop on each will be sufficient. Then wash in a drop of 

 alcohol and wipe with a smooth linen cloth. If it be desired 

 to have the slides chemically clean, soak them in strong 

 sulphuric acid containing some cr3^stals of potassic bichromate, 

 allowing the slides to remain several days in the liquid. 



To Preserve Algae. — Camphorated water and distilled 

 water, each 50 grannnes ; glacial acetic acid, 5 gr. ; crystallized 

 nitrate of copper, each 2 grammes ; dissolve and filter. Speci- 

 mens thus prepared will retain their living appearance. 



To Fix Cilia of Infusoria. — In a drop of water containing 



