Making the best of things: reclaiming specimens

x 1 inch slides in Canada balsam. This is a longterm system and, although Canada balsam may darken with age, especially if exposed to light, it remains transparent and usable for over 60 years, in contrast to plastic mountants which deteriorate too rapidly for use on archival material. ( Some plastic mountants form an opaque, crystalline deposit at the exposed edges which progresses inwards and, after about 5 to 10 years, the whole preparation becomes opaque. Others develop a crazed surface from which the cover-glass often becomes detached). The slides are stored flat, in trays each carrying 20 slides which are kept in boxes holding about 6 to 8 trays. These trays, with over-all dimensions of about 34 x 2Ocm, are of a convenient size to be placed on the bench beside a microscope. The slides are stored in systematic order and those bearing type specimens bear a red spot. R.A. Bray 253