LKCT. X.] ANATOMY OF LEAVES. 593 



in close contact with the vessel (a. .), but neither 

 spring out of it, nor appear to have any direct 

 communication with it; and that neither the elon- 

 gated cells (b.b.b.b.b.), nor the spheroidal (d.d. d.), 

 appear to communicate with one another by any 

 tubular production. The transparency of the cellu- 

 lar membrane produces an appearance (c. c. e.e.e ) 

 at the points of contact of the cells, which might 

 be mistaken for small tubes, but which arises from 

 the impression of the contiguous cells upon one 

 another. Even in that peculiar modification of the 

 cellular structure, which is found immediately with- 

 in the cutis of the inferior disk of some leaves; and 

 in which the cells assume the appearance of ana- 

 stomosing tubes (3Q.), none of the tubular connect- 

 ing processes, described by Malpighi, are perceived; 

 nor do these cells appear to communicate directly 

 with the vessels which they surround. As this is the 

 most curious modification of the cellular structure 

 of leaves, I shall demonstrate it to you as it 

 appears in the floral leaf of Helleborus viridis, 

 which I select for this purpose, from its being 

 almost devoid of colour. In the minute portion 

 before us, as it appears under the microscope, we 

 perceive the range of cells e. e. (39) closely ap- 

 plied to the proper vessels d. d. but not communi- 

 . eating with it: the cells c. c. c. c. assume various 

 forms, but all are apparently tubular ; and, where 

 they are more transparent than common, we dis- 

 VOL. i. Q Q 



