THE MICROSCOPE. 143 



SCIENCE-GOSSIP. 



Method of Mounting Calcined Microscopic Specimens. 

 — Mr. J. Mansbridge finds the one great disadvantage in the 

 use of fluid balsam as a mounting medium for calcined speci- 

 mens, where it is advisable to retain the air in the structure for 

 purposes of clear definition, is the liability to run into any 

 spaces, such as lacunae or tubuli that may exist in the tissue. 

 To overcome this difficulty, he uses dessiccated balsam in the 

 following way : — Take a clean slide, place it upon a hot table 

 with a small lump of balsam upon it, and cover with a hot 

 cover glass, which must be pressed down in such a way as to 

 expel all air from beneath it. Remove the slide to a cool sur- 

 face and continue to keep pressure upon the cover glass for a few 

 minutes, when the balsam will be found to be quite hard and 

 the specimen ready to be labelled and to be putaway. He finds 

 the advantages : (1) There is no chance of the mounting me- 

 dium running in and spoiling the section, as it becomes per- 

 fectly hard a few minutes after removal from the hot table 

 (2) The specimen is finished at the time and is ready for the 

 cabinet. There is no need to use a clip, no fear of the cover- 

 glass shifting if the slide is placed upon its side. (3) It is very 

 convenient for teaching purposes, as the ordinary stiff balsam 

 soon gets into a most deplorable condition. — Trans. Odont. So- 

 ciety. 



To Make Gold Crystals. — Get some neutral terchloride of 

 gold and make a solution of about ten per cent in strength ; 

 put into it a piece of zinc, and you will see an immediate out- 

 growth of black metal, then the gold will push forward inlichen- 

 like masses, green, lilac, or yellow, followed, perhaps, by yellow 

 or black fringes, and ending in delicate aborescent forms. A 

 yellow branch will often run rapidly around the edge of the 

 drop. The gold salt is also apt to crystallize on the glass plate 

 in long needles and the metallic fronds follow up these long 

 crystals which disappear before them as though devoured by 

 their advancing points. — Boston Journal of Chemistry. 



To Take Aniline Stain Out of Cloth. — Dissolve one part of 

 Sodium Nitrate in two parts of dilute sulphuric acid and 75 

 parts of distilled water. Let it stand over night. Apply gently 

 and rinse carefully. 



