244 



HISTORY OF SCIENCE. 



stances the cells may become elongated, as in Fig. i T 6 ; and by the 

 absorption of the transverse partitions, they do in many cases pass 

 into the form of tubes, and thus form the well-known fibres and ducts 



FIG. 116. 



FIG. 117. 



of vegetable tissues. In Fig. 117, which represents fibres from the 

 root of the elder-tree, this formation from originally separate cells can 

 be distinctly traced. 



.- s** 



