372 THE WOELD OF LIFE 



But later on we have a much fuller description, illustrated 

 by four diagrammatic figures of the dividing cell, which show 

 that the process in plants is substantially identical with that 

 described and figured already from Weismann (vol. i. p. 

 581). This is most instructive, because it shows the absolute 

 identity of the fundamental mechanics of life in the animal 

 and vegetable kingdoms, though their ultimate developments 

 are so wonderfully diverse. 



Another interesting point is that, just as Weismann has 

 stated, there is an identity in the number of certain elements 

 in the cell for each species. Kemer's statement is : 



" For every species of plant the number, size, and shape of the 

 bodies arising in the interior of a cell by division are quite definite, 

 though they vary from species to species. In the cell-chambers of 

 some species several thousand minute protoplasmic bodies arise. 

 In others, again, the number is very limited. If the number is 

 large the individual masses are exceedingly small, and can only be 

 recognised when very greatly magnified. If the number is limited 

 the divided portions are comparatively large. The shape of the 

 structure is exceedingly various. Some are spherical, elliptical, or 

 pear-shaped; others elongated, fusiform, filamentous, or spatulate; 

 some are straight, others are spirally twisted, and many are drawn 

 out into a thread; others are provided over the whole surface with 

 short cilia; others, again, with a crown of cilia at a particular 

 spot, or with only a single pair of long cilia. In the majority of 

 cases the small bodies exhibit active movements; but sooner or 

 later they come to rest, and then assume another shape or fuse 

 with another protoplasmic body." 



Referring to the theory that the structure of each plant 

 is due to the specific constitution of the protoplasm of the 

 species, Kerner says : 



" What it does not account for is the appropriate manner in 

 which various functions are distributed among the protoplasts of 

 a cell-community ; nor does it explain the purposeful sequence of 

 diiferent operations in the same protoplasm without any change 

 in the external stimuli; the thorough use made of external ad- 



