308 The Microscope. 



another. I have also used a varnish made of shellac dissolved in 

 methylated spirit, and, as this is brittle, I add about one-eighth 

 gutta percha. This is a useful cement for gelatin and glycerine 

 mounts. The rings should have one or two coats of pure varnish as 

 a~ finish. 



Demonstration of Bile-Capillaeies. — For the demonstration of 

 the biliary capillaries, Dr. M. Muira used the following methods: 

 (Virchows Arch. F. Pathol- Anat xcix, 1885,) A small piece of liver, 

 after having been in Miiller's fluid for 25 days, is washed with ordi- 

 nary water and laid in distilled-water for 35 hours. It is then 

 transferred for 28 hours to a 15 per cent, watery grape-sugar solu- 

 tion. It is next placed for two or three days in a 0.1 to 0.2 per cent, 

 solution of gold-chloride. The gold solution is to be changed two 

 or three times. Finally the preparation is again left for two or three 

 days in the grape-sugar solution, but without access of air, until it 

 assumes a dark-violet or black coloi". The bile- capillaries are stained 

 a pui'ple red. — Jr. R. M. Society. 



Directions for using Prof. H. L. Smith's High Refractive 

 Mounting Media.* — -Use barely enough of the medium to fill in 

 under the cover when the slide is warmed ; it does not materially 

 diminish by any subsequent heating. 



Boil thoroughly under the cover, and until all bubbles dis- 

 appear on allowing the slide to cool ; if any should still remain they 

 may be readily coaxed out by proper application of a small flame. 



When the slide is cold the cover should remain firmly fixed; 

 any excess of the medium must be removed by means of a moist 

 cloth or a roll of moistened tissue paper. The cleaning must be 

 thorough ; all excess must be removed around the edge of the cover, 

 as otherwise it is liable to act upon the cement, or finishing ring. 

 If, after the cleaning, the cover shows metallic stains, do not 

 attempt to clean them off until after the finishing ring is hard. 



When the excess has been removed around the edge of the 

 cover, gently warm the slide to drive off the small amount of mois- 

 ture that may have been absorbed during the cleaning. When 

 again cooled apply a protecting ring of asphalt-black or white- zinc 

 or — perhaps better if one will take the trouble to make them — a 

 wax ring, punched from the sheet- wax used for artiiical flowers. 

 The wax ring is a sure protection, especially for the highest medium, 



♦Fiirnishert by the Palmer Sli.le C< 



