Z06 APPENDIX II 



be well moistened with glycerine if it is to be mounted in glycerine-jelly ; but, 

 if not, it must, directly after being cut, be dehydrated by being soaked in 

 methylated spirit and dried between blotting-paper. It is best to drop the 

 curling shaving at once into some Liquid dye, as this renders the structure far 

 more readily visible imder the microscope. An alcoholic solution of methyl 

 violet does very well; but, perhaps, erythrosin, which can be obtained in 

 tabloids, is the best all-round stain for microscopic work. For micro-photo- 

 graphy fuchsin gives sharper contrasts. After dyeing, the thinner part of 

 the shaving can be cut square with scissors and mounted, for which purpose 

 we personally prefer an extra wide glass sHp and a square cover-glass. If 

 carefully dried with blotting-paper under moderate pressure the sections can 

 be preserved unmounted, or mounted, as permanent microscopic objects in 

 Canada balsam or in glycerine-jelly under thin glass cover-slips, or on paper, 

 like the series prepared by Herr Nordlinger. 



Another method we have found e£acacious is to immerse a small squared 

 specimen in a basin of water— such as a deep photographic basin — by means of 

 metal weights, and then to sHce of! thin shavings with a broad chisel. The 

 sections floating to the surface may then be dyed, or may be simply floated 

 on to sHps of glass, lightly covered with thin cover-slips and then dried slowly 

 and cemented down. Though most students of minute structure use thin 

 cover-slips, excellent results are attainable with thick ones, such as the glass 

 ordinarily used for photographic negatives. 



Though the transverse section is most important, longitudinal ones, either 

 radial or tangential, are often also of use — the latter, for instance, affording 

 the readiest means of distinguishing Alder from Birch. 



Such mdcroscopio sections can be most readily studied by being used with 

 a lantern ; but when so used they should always be protected from the heat 

 of the burner by an alum bath. 



Nothing is more likely to impress the facts of structure upon the student's 

 mind than the fixing of the image of that structure as projected by the lens 

 of a lantern by means of photography. This can be carried out without 

 costly apparatus — that used by Mr. Weale in the preparation of the photo- 

 graphs for Appendix IV. not costing five shillings, in addition to the price of 

 the lens. 



