PROPAGATION OF PLANTS. 19 



almost every different variety of the Eose has an indi- 

 vidual fragrance of its own, which is only emitted while 

 the cells remain in their natural and original form. 

 The bark-cells of many species of plants yield valuable 

 products not to be found in any considerable amount in 

 other parts of the same plant, as in the bark of the Cin- 

 namon tree, Benzoin, Peruvian bark, and in the root-bark 

 of the Sassafras. In other plants the roots may yield a 

 large amount of coloring matter, as in those of the 

 Madder, while only a trace of it appears in the stems and 

 leaves. Seeds of some kinds of plants yield oil in the 

 greatest profusion, with little or none in other parts; Flax, 

 Rape and Cotton seed are familiar instances of this kind. 

 Some seeds contain most powerful poisons, like those of 

 the Strychnos, while the pulp surrounding them is in- 

 noxious. The Peach tree yields the most luscious of 

 fruits, while from the seed maybe extracted Prussic acid, 

 the most virulent of all known vegetable poisons. 

 Special deposits of special elements in the same plant 

 may be considered the rule in nearly all of those most 

 useful to man, and yet all these various substances are 

 derived from the same sources, and are composed of 

 simple elements, known by less than a half dozen differ- 

 ent names. A plant, therefore, is in itself a chemical 

 laboratory, and within its minute cells systematical evolu- 

 tions are in progress, which we can neither see or fully 

 understand, but the results are quite apparent to some 

 one or all of our senses. 



