COURSE OF THE SAP. 



tliey are the stomach, lactcals and arteries all 

 in one, lor I conceive it to be a great error in 

 Dr. Darwin to call by this name the vessels 

 wliicli contain ilic peculiar secretions of the 

 plant*. These sap-\ essels, no doubt, absorb 

 the nutritious fluids afforded by the soil, in 

 ivhich possibly, as they pass through the root, 

 some change analogous to digestion may take 

 place; for there is evidently a great difference, 

 in many cases, between the fluids of the root, 

 at least the secreted ones, and those of the rest 

 of the plant ; and this leads us to presume that 

 some considerable alteration may be wrou2;ht 

 in the sap in its course through that impor- 

 tant organ. The stem, uhich it next enters,, 

 i^ by no means an essential part, for we see 

 many plants whose leaves and flowers grow 

 directlj' from tiie foot. 



Part of the sap is co-uveyed into the flowers 

 and fruit, where various fine and essential se- 

 cretions are madxj from it, of which we shall 

 speak hereafter. By far the greater portion 

 X)f the sap is carried into the leaves, of the 

 great importance and utility of wifich to the 

 pjant itself Mr. Pvnight's theory is the only um.. 



^ Phijtologin, ^cct. Q, 



