PHYTO-PHYSIOLOGY. 257 



the hollow stalks, the interstices and cells of the pith 

 and cuticle. It imparts the process of oxydation. The 

 water is the proper mother of the plant, being the 

 medium by which the nutrition is imparted. It contains 

 in a state of absorption some hydrogen and nitrogen, a 

 larger amount of oxygen, and abundance of carbonic 

 acid ; besides different salts, mucus, sugar, and acids. 

 The earth, as element, bestows upon the plant a firm sta- 

 tion, so that the water- and air-organs continue separate 

 from each other. 



* 



Minerals or Earths. 



1367. The plant is also a totality in reference to the 

 earths. It contains all the mineral classes, and from each 

 of these indeed the principal or fundamental minerals. 

 It can therefore only thrive in a soil which represents the 

 whole mineral kingdom. Among the earths the siliceous 

 earth is very frequently found in plants, and especially in 

 the graminaceous kinds. This, having been dissolved 

 in the earth by potash and the rich supply even of car- 

 bonic acid, appears to be absorbed or imbibed by the 

 plant. The argillaceous earth is scarcely met with in the 

 plant itself; but from imbibing and storing up water for 

 the consumption of the plant, it is without doubt its best 

 and most necessary soil. The talcose earth is rarely 

 found contained in plants ; it, however, keeps the soil 

 slacker, by dividing into lamina?, and being present for 

 the most part as mica in sand. The calcareous earth 

 is a more essential constituent part of plants, and is 

 found therein in tolerable quantity, usually combined with 

 phosphoric or carbonic acid Of the salts, all plants con- 

 tain a fair proportion of common salt and potash, com- 

 bined too with carbonic acid ; soda with saccharic or 

 oxalic acid ; probably also ammonia. Of the acids, 

 carbonic acid appears to be alone contained in a free 

 state in vegetable sap ; the other elemental and mineral 

 acids are united to alkalies, talcose and calcareous earths, 

 As regards the Inflammables, almost the whole plant 

 consists of carbon, but contains also some sulphur. The 



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