CRFSTALS IN THE CELLS OF PLANTS. 6 J 



the mesophyll of Begonia) ; when, on the other hand, a crystal, or a chister, or a bundle 

 of raphides, or finally a mass of small crystals, nearly fills up a cell, no other constituent 

 of definite form is usually present; it appears as if, in such cases, the cell is usually 

 approaching a condition of rest or even of slow dissolution ; if at an earlier stage a 

 larger mass of crystals has been formed in a cell, it often remains smaller and with 

 thinner walls than its neighbours. The cells which contain raphides show loosened walls 

 which easily swell, and the bundles of raphides are generally surrounded by a thick 

 gummy mucilage. A similar reason also explains why the granules and crystals deposited 

 in the cell-wall of Gymnosperms usually lie in a softened mucilaginous middle lamella or 

 in the cuticularised layers of the epidermis ^ . 



^ [Professor Mf'Nab gives (Journal of Botany, new series, vol. i. p. 33) for the composition of 

 the potassium-chlorate solution : three grains of potassium-chlorate dissolved in two drachms of 

 nitric acid of sp. gr. i-io. The preparation of ' Schultz's solution' is thus described by Schacht 

 (The Microscope and its application to vegetable anatomy and physiology, translated by F. Currey, 

 p. 43): Zinc is dissolved in hydrochloric acid; the solution is allowed to evaporate under contact 

 with metallic zinc, until it attains the thickness of a syrup; the syrup is then saturated with 

 potassium iodide, the iodine added, and the solution, when necessary, diluted with water. For the 

 ' iodine-solution ' the same authority recommends one grain of iodine, and three grains of potassium 

 iodide in one ounce of distilled water.^Ko.] 



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