154 VEGETABLE CELLS. 



between origin and growth. But if these two ideas are not 

 absolutely different from each other, we shall still let them 

 stand side by side as separate, in their relative difference. 



When a cell is produced, a portion of organic matter 

 becomes individualized and inclosed by a membrane, 

 through secretion of organic substance. With CELL- 

 FORMATION, therefore, is connected an individualization of 

 organic matter and a formation of new membrane. When 

 apical growth begins at a point of the surface of a cell, 

 and a branch-cell is formed, a portion of homogeneous 

 mucilage appears, which secretes membrane from within 

 outward. With the commencement of APICAL GROWTH, 

 therefore, is connected the individualization of a portion 

 of the contents and a formation of neiv membrane, and, 

 with the continuous APICAL GROWTH, a continuous for- 

 mation of new membrane. I will consider these two 

 points a little more minutely. 



When secondary cells originate in a parent-cell, definite 

 portions of the contents are repeated in such a manner, 

 that from that time they possess an individual existence, 

 having been up to that period undistinguished parts of 

 the parent individual. When a branch is produced upon 

 a cell, a definite portion of the contents is likewise sepa- 

 rated, and indeed a small portion of the mucilaginous 

 layer. This has from that time an individual vitality 

 wholly distinct from all the rest of the contents. This 

 little portion of mucilage is the rudiment from which a 

 new branch is produced. The branch of the ramified cell, 

 however, has quite the same import as the branch of a 

 many-celled plant. In the ramified cell, as in the many- 

 celled plant, it may, under certain circumstances, be de- 

 tached and become an independent, new, and individual 

 plant. 



With the commencement of the APICAL GROWTH in the 

 formation of a branch, consequently, is connected the indi- 

 vidualization or separation of a portion of the contents, as 

 well as with cell-formation. 



These secondary cells originate in a parent-cell ; the 



