252 CHAPTER XX. 



all cases in which it is desired to cement glass to glass. 

 Used warm. 



471. Turpentine, Venice Turpentine (CSOKOR, Arch. mik. 

 Anat.j xxi, 1882, p. 353 ; PARKER, Amer. Hon. Mik. Jo urn., 

 ii, 1881, pp. 229-30). Venice turpentine, or common resi- 

 nous turpentine, evaporated by heat until brittle on cooling. 

 It is used for closing glycerin mounts in the following 

 manner : Square covers are used, and superfluous glycerin is 

 cleaned away from the edges in the usual way. The cement 

 is then put on with a piece of wire bent at right angles ; 

 the short arm of the wire should be just the length of the 

 side of the cover-glass. The wire is heated in a spirit lamp, 

 plunged into the cement, some of which adheres to it, and 

 then brought down flat upon the slide at the margin of the 

 cover. The turpentine distributes itself evenly along the 

 side of the cover, and hardens immediately, so that the slide 

 may be cleaned as soon as the four sides are finished. It 

 is claimed for this cement that it is perfectly secure and 

 never runs in. It sets hard in a few seconds. 



472. Colophonium and Wax (KRONIG, Arch. mik.Anat., 1886, 

 p. 657). Seven to 9 parts of colophonium are added piece- 

 meal to 2 parts of melted wax, the whole filtered and left 

 to cool. For use, the mass is melted by placing the contain- 

 ing vessel in hot water. The cement is not attacked by water, 

 glycerin, or caustic potash. 



VOSSELER (Zeit. li'lss. M'ik., vii, 1891, p. 462) takes 1 part 

 of Venice turpentine to 2 to 3 of white wax. 



473. APATHY'S Cement for Glycerin Mounts (Zeit. wiss. Mik., 

 vi, 1889, p. 171). --Equal parts of hard (60 C. melting-point) 

 paraffin and Canada balsam. Heat together in a porcelain 

 capsule until the mass takes on a golden tint and no longer 

 emits vapours of turpentine. Used by warming and apply- 

 ing with a glass rod or brass spatula. One application is 

 enough. Does not run in, and never cracks. 



474. Canada Balsam, or Damar. Cells are sometimes made with 

 these. They are elegant, but in my experience are not reliable for per- 

 manent mounts. 



475. Amber Varnish. BUHRKNS finds this cement to possess 



