142 PROSERPINA. 



the cambium which becomes bark : but at page 128, the 

 thin walled cells of the bark are said to be those of ordi- 

 nary ' parenchyma,' and in the next page a very import- 

 ant passage occurs, which must have a paragraph to 

 itself. I close the present one with one more protest 

 against the entirely absurd terms ' par-enchyma,' for com- 

 mon cellular tissue, ' pros-enchyma,' for cellular tissue 

 with longer cells ; ' cambium ' for an early state of both, 

 and ' diachyma 'for a peculiar position of one \ * while the 

 chemistry of all these substances is wholly neglected, and 

 we have no idea given us of any difference in pith, wood, 

 and bark, than that they are made of short or long 

 young or old cells ! 



22. But in Dr. Gray's 230th article comes this passage 

 of real value. (Italics mine all.) "While the newer 

 layers of the wood abound in crude sap, which they con- 

 vey to the leaves, those of the inner bark abound in 

 elaborated sap, which they receive from the leaves, and 

 convey to the cambium layer, or zone of growth. The 

 proper juices and peculiar products of plants are accord- 

 ingly found in the foliage and bark, especially the latter. 

 In the bark, therefore, either of the stem or root, medi- 

 cinal and other principles are usually to be sought, rather 



* " ' Diachyma ' is parenchyma in the middle of a leaf !" (Balfour, 

 Art. 137.) Henceforward, if I ever make botanical quotations, I shall 

 always call parenchyma, By-tis ; prosenchyma, To-tis ; and diachyma, 

 Through-tis, short for By -tissue, To-tissue, and Through -tissue then 

 the student will see what all this modern wisdom comes to ! 



