PHYTO-PHYSIOLOGY. 265 



1400. The vessels of plants are notwithstanding to be 

 compared with the lymphatic vessels of animals, in so 

 far also as these are distributed throughout the whole 

 body, and convey the sap simply in one direction not in 

 a circle. 



1401. As the passages between all the cells are in all 

 directions, so the vegetable saps or fluids flow in all 

 directions, and not to one centre as in the animal. 

 Plants have no heart. The sap pursues a tolerably 

 rapid course in the vessels. A fading or drooping cab- 

 bage, two feet in length, can gradually become erect in 

 a few minutes after being put to soak in water. In 

 other respects the course of the sap in the vessels may 

 be seen in many plants under the microscope. 



b. Liber-process Mixture of Sap. 



1402. In the liber, as being the mass of intercellular 

 passages, the sap contained in the vessels principally ac- 

 cumulates, as in the thoracic duct of animals ; in it the 

 matters have not been simply conveyed and dissolved, 

 but also mixed and converted into true vegetable sap, 

 into blood. 



1403. The tubes of the liber are those by which the 

 chemical life is sustained. 



c. Stalk-process Secretion. 



1404. The stalk is the root planted in air, and conse- 

 quently its process is the differenced process of putre- 

 faction, in which the mucus becomes further evolved. 



1405. The analysis chiefly occurs in the stalk; the 

 mucus, or rather the starch, becoming converted into 

 sugar and acids. 



1406. Sugar is the mucus of the stalk, and is found 

 in every vegetable sap, especially that of such plants as 

 are characterized by the systems of the stalk, and have 

 not yet attained the formation of the reticular leaf, as the 

 Monocotyledones, e. g. the grasses. 



1407. The sugar originates from a process of fernien- 



