SECT. II. ASCENT OF THE SAP. 1O1 



the original organization is obliterated; nor by that 

 of the larger and more aged branches. But it has 

 been thought there are even some of the soft and 

 succulent parts of the plant by which it cannot be 

 effected, because no pores are visible in their epi- 

 dermis. M. Decandolle found no pores in the 

 epidermis of fleshy fruits, such as Pears, Peaches, 

 and Gooseberries ; nor in that of roots, or scales of 

 bulbs ; nor in any part not exposed to the influence 

 of air and light. It is known, however, that fruits 

 will not ripen, and that roots will not thrive, if 

 wholly deprived of air; and hence it is probable 

 that they inhale it by their epidermis, though the 

 pores by whjich it enters should not be visible. In 

 the root, indeed, it may possibly enter in combi- 

 nation with the moisture of the soil ; but in the 

 other parts of the plant it enters no doubt in the 

 state of gas. Herbs, therefore, and the soft parts 

 of woody plants, absorb moisture and inhale gases 

 from the soil or atmosphere by means of the pores 

 of their epidermis, and thus the plant effects the 

 intro-susception of its food, 



SECTION II. 

 Ascent of the Sap. 



IN tracing out the means by which the plant 

 effects the intro-susception of its food, it was found 

 to be chiefly that of absorption by the root. But 



