PHYTO-PHYSIOLOGY. 263 



contains carbon and water. The calcareous soil is as it 

 were an original mould. It is probable that the calca- 

 reous earth is constantly decomposed by the root and its 

 carbon absorbed. The calcareous earth is again neu- 

 tralized by the carbonic acid of the water and air. 



1389. There can be no doubt that the root also 

 abstracts carbon from these elements, and converts it 

 into mucus, or probably separates it from carbonic acid. 

 The mucus approximates the animal nature, so that the 

 root in its constituent parts, in its smell, and even in its 

 structure, exhibits animal properties ; animal substances 

 therefore are also the best nutritive media of plants. 



1390. That which putrefies most easily is the best 

 manure. 



1391. Through the process of putrefaction many kinds 

 of antagonisms and attractions, by which the absorption 

 takes place through the root-filaments, are aroused. 



1392. The root has not merely one orifice for absorb- 

 ing, but it imbibes upon the whole surface, from its being 

 still immersed in the chemical menstruum. The integu- 

 ment of animals does the same. 



b. BARK-PROCESS EVAPORATION. 



1393. The bark, as an organ of cellular tissue, which 

 is placed wholly in the outward direction, must princi- 

 pally exercise the process of absorption and evaporation. 

 Now, as there are two kinds of bark, a root- and a stalk- 

 bark, or a water- and air -bark, so upon the former will the 

 business of absorption chiefly devolve, on the latter that 

 of evaporation. 



1394. As the bark of the stalk possesses stomata, 

 which are wanting in that of the root, so is this a pro- 

 bable reason for these apertures being organs of evapo- 

 ration. This opinion is corroborated also by aquatic leaves 

 being without stomata, while they occur in the leaves 

 exposed to air. 



1395. Meanwhile the stalk is of a twofold character; 

 it is only the root that has ascended into the air. As an 

 aerial root it absorbs. Without doubt the stalk absorbs 



