OF THE LEAVES, &C. 8'5 



of papers reciting a number of experiments that 

 he made, and which he considered to confirm 

 the fact. And Sir H. Davy conforms to his 

 opinions, and says, " In all plants there exists 

 *' a system of tubes or vessels, which, in one ex- 

 " tremity, terminates in the roots, and at the 

 " other in leaves. It is by the capillary action 

 ** of the roots, that fluid matter is taken up from 

 " the soil. The sap, in passing upwards, be- 

 " comes denser, and more fitted to deposit solid 

 " matter ; it is modified by exposure to heat, 

 " light, and air, in the leaves ; descends through 

 " the bark, in its progress produces new organ- 

 " ised matter, and is thus, in its vernal and 

 ** autumnal flow, the cause of the formation of 

 " new parts, and of the more perfect evolution 

 *' of parts already formed." 



But Mrs. Ibbetson, (a lady who has studied 

 the organism of plants, aided by a powerful 

 solar microscope, and whose observations and 

 descriptions are published in a series of papers 

 in Nicholson's Philosophical Journal,) after giv- 

 ing a variety of reasons which induce her to 

 conclude that the sap does not circulate, says, 

 "How strange, then, to alter all this beautiful 

 " arrangement, justified, indeed taught b}"^ dis- 

 *' section, in order to find a place for sap-vessels, 

 *' that cannot possibly require any. For' why 



G 3 



