APPENDIX I 



1425. Cleaning Slides and Covers. New ones should first be 

 soaked in one of the following liquids : strong sulphuric, hydro- 

 chloric or nitric acid, or aqua regia, or a mixture of an ounce 

 each of sulphuric acid and bichroniate of potash with from 

 8 to 12 ounces of water, then washed first with water and lastly 

 with alcohol, and dried with a clean cloth. 



For used ones, if a balsam mount, warm, push the cover into 

 a vessel with xylol or other solvent of the mount, and put the 

 slide into another vessel with the same, leave for a few days and 

 then put into strong alcohol. If this is not sufficient, treat as 

 for new ones. Some persons boil in lysol, which we do not find 

 efficacious. 



For the final treatment, see § 208. 



For chemically free vessels, see § 779. 



1426. Gum for Labels. Labels stuck on glass often strip off. 

 This may be avoided (Marpmaxx, Zeit. Angew. Mik., ii, 1896, 

 p. 151 ; Journ. Roy. Mic. Soc, 1897, p. 84) by means of the 

 following adhesive : 120 grm. of gum arable are dissolved in a 

 quarter of a litre of water, and 30 grm. of gum tragacanth in a 

 similar quantity. After a few hours the tragacanth solution is 

 shaken until it froths, and mixed Avith the gum arable solution. 

 Strain through linen and add 150 grm. of glycerin previously 

 mixed with 24 grm. of oil of thyme. 



1427. Marking Slides Instead of Labels. For many years, 

 quick-drying varnishes, etc., have been used for marking slides. 

 Transparent lacquer is advocated by Philip Smith, who paints the 

 end portion of the slide with " liUC," allows to dry, writes the 

 title, and covers the writing with another* coat (Watson's Micro- 

 scope Record, No. 16, 1929). Similar paint can be made by 

 dissolving celluloid in amyl acetate. 



Peirce (Journ. app. Mic, ii, 1899, p. 627 ; Journ. Roy. 

 Mic. Soc, 1900, p. 404) finds that if the end of the slide be painted 

 with a thin solution of balsam, it may be written on with ink 

 when dry, and the record preserved by a second coat painted 

 over it. 



For other receipts see earbi editions. 



1428. J. Baker's Method for Pressing Down a Coverslip. 

 While a balsam or glycerin-jelly moiuit is hardening, place the 

 slide flat and put a small cork (from a specimen tube) on the 

 middle of the coverslip. Put enough pennies on the cork to give 



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