I Pitcher Plants 13 



slices from its surface, and mounting them in a drop of 

 water between slide and cover-glass. These, however, we 

 probably find to be comparatively opaque and confused, 

 because too thick, and including much of the deeper 

 leaf- tissue or parenchyma as well as epidermis. We 

 may, it is true, improve our preparation by the use of 

 methods familiar to every microscopist, e.g. by washing 

 the preparation in spirit to dissolve out the green colouring 

 matter or chlorophyll, by treatment with caustic potash 

 solution to destroy even the protoplasm, by dyeing or 

 staining the cell-walls conveniently with a solution of one of 

 the anilines to bring out their outlines more clearly, and by 

 mounting in glycerine instead of water, so as to give greater 

 transparency to the whole. Instead of all this trouble, which 

 after all will not make a good preparation out of a badly- 

 made section, we may learn much from even a thick slice 

 in the fresh state by observing merely its edges, which are 

 sure to be somewhere thin enough. A better method how- 

 ever, which, with a little practice, will be found to give 

 excellent preparations, not only of all the tougher-leaved 

 insectivorous plants, but of any tolerably strong epidermis, 

 is to lay the morsel of leaf face downwards upon a slide in 

 a large drop of water, and then holding it firmly at one 

 edge, to scrape away with a sharp scalpel or penknife the 

 other epidermis and the green leaf-tissue, the veins too, as 

 far as they will come, washing the debris from the prepara- 

 tion from time to time, and scraping more carefully and 

 lightly as the lower epidermis is exposed, and of course 

 threatens or begins to tear. When tolerably clean the 

 preparation may be turned over and examined, a funda- 

 mental principle in all microscopic study being first to 

 make out all one can with the low magnifying power before 

 proceeding to a higher one, while the various operations of 

 histological ^^ cuisine" above indicated may be applied if 



