LECT. X.] ANATOMY OF LEAVES. 569 



leaves, are placed between two bundles of proper 

 vessels. If we cut a superficial slice from the under 

 disk of the leaf, where any of the fasciculi ra- 

 mify (25. see page 567); and examine it by a 

 powerful microscope, we may rationally conclude 

 from what we perceive, that, although some of 

 the costse are merely continuations of the vas- 

 cular fasciculi of the midrib, separated like threads 

 from a skein of silk, yet that others which also 

 branch from these, and the smaller transverse 

 vascular threads, are actually united by that 

 kind of connexion which, in the vessels of animals, 

 is termed anastomosis. Thus, in the slice under 

 examination, we find that both the fasciculi (a. a.) 

 contain the same number of vessels, which would 

 not be the case, were the one parcel separated from 

 the other ; and although the transverse thread (b.) 

 contains one spiral vessel only, yet this vessel does 

 not appear to be split from the larger fasciculus ; 

 but to be simply united to it, the end of b. being 

 evidently applied to the side of a. if it do not ac- 

 tually open into the cavity of that vessel. 



Examining, by the same power of the micro- 

 scope, a transverse section of one of the larger 

 fasciculi of the midrib of the leaf of Canna In- 

 dica, we find it to consist of one large, and 

 from three to six smaller spiral vessels, arranged 

 and relatively connected with the proper vessels 

 in a manner closely resembling the arrangement of 

 those in the fasciculi which are found in the 



