182 THE MICROSCOPE. [August, 



63. Which is the best of the cos in clyes^ the blzie, red^ or 

 yelloiv ? 



Use the red shade, make a rather weak solution in water, wash 

 the stained sections in water containing a little acetic acid. 



64. / have so?ne microphotographs on small glass beads. 

 Hoiv may I mount them on glass slips? 



These photos are usually covered with a piece of glass cemented 

 with balsam. Soak in benzole until separated, place a drop of 

 balsam on the centre of a cover-glass, put the bead in the balsam, 

 photo face next the cover ; let it harden under a glass shade, mount 

 in a cell deep enough to take the bead. 



65. What are the points of difference betweeri Bis7narck 

 brown., vesuvine., chrysoidine^ etc? 



Where can I find a description of the uses of oxalate of 

 rosaneline and twelve other aniline dyes na?ned? 



What is the difference between the various aniline violets 

 and purples ? 



What are the points of difference in the variotis aniline 

 blues ? 



It would be unprofitable to devote time and space to answer 

 the above queries in full. The literature is scattered and is mostly 

 worthless reports of hasty work. Added to this, the fancy trade 

 names applied to these dyes make identification difficult. The 

 aniline colors are brilliant, but as a rule stain diffusely, fade 

 quickly, and have a restricted value for temporary study mounts. 

 A real service would be accomplished if some one would procure 

 authentic specimens of these colors, make a large number of stain- 

 ings and report, after a year, in some prominent journal. 



The Am. Mo. Mic. fournal., vols. VI and VII, contains a 

 series of translations from the German of Hans Gierke on stain- 

 ing tissues, valuable and full. 



(y^. Will you kindly give an amateur easy directions how to 

 draw microscopical objects., and which is the best or cheapest 

 instrufnent to use? 



A neutral tint camera lucida is the cheapest camera. Focus 

 the object, attach the camera to the eye-piece, turn the micro- 

 scope tube to a horizontal position ; place the drawing paper, 

 beneath the camera, on the table ; adjust the illumination on paper 

 and object until both are distinct when the eye is in position, 

 closely above the camera. Practice drawing until you become 

 expert. The camera lucida is used to obtain correct outlines only. 

 The details are to be filled in from memory, after repeated ex- 

 aminations, without the camera. 



