THE VEGETABLE CELL 



301 



In a few cases, cells are found to contain crystalloids of 

 proteid not included in an aleurone grain. Such bodies occur 

 frequently in certain parts of the tuber of the Potato, and in 

 some Seaweeds. 



Fats CMid Oils. — Certain cells, generally in the fruit or seed, 

 contain fats or oils saturating the protoplasm, or sometimes 

 occupying nearly the whole of the cell-cavity. Ethereal oils are 

 found similarly in cells of various parts of the leaves or stems, 

 usually in small aggregations of cells in the interior of the 

 tissue, or in cells of the hairs which grow from the epidermis. 

 These are generally spoken of as oil-glands, or glandular hairs. 



Besins. — In certain plants, particularly those belonging to the 

 natural order Coniferae, certain aggregations of cells are found 



Fig. 656. 



FiCr. 657. 



Fig. 658. 



Fig. 669. 



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J-'iif. 656. Solitary crystals in tlie cells of the bark of the Locust tree. After 



Uray. Fig. 657. Conglomerate raphides or sphferaphides of the Beet. 



Fig. 658. Acicular or true raphides of a species of Rumex. Two cells 



contain raphides, and three of them chlorophyll granules. Fiij. 659. 



True or acicular raphides of an Arum being discharged tltrough endos- 

 mosc under the influence of water. 



to contain quantities of peculiar material, . generally termed 

 resin. This material is different in composition in different 

 plants ; it may be recognised by staining red with alcoholic 

 tincture of alkannin. It is soluble in alcohol, benzol, and ether, 

 but insoluble in any waterj' fluid. 



Baphides. — This name is now more generally applied to all 

 inorganic crystals of whatever form which are found in the cells 

 of plants, although the term raphides was originally given to 

 those only that had the form of a needle {Jigs. 658 and 659). 

 Baphides may be found more or less in nearly all orders of 

 plants, and in aU their organs ; generally, however, they are 

 most abundant in the stems of herbaceous plants, in the bark 

 of woody plants, and in leaves and roots. In some plants they 



