68 



CHAPTERS ON EVOLUTION. 



Selecting the field of plant-life for our next essay on the powers and 

 nature of protoplasm, we find in this particular region abundant proof 

 that the peculiarities of protoplasm are in nowise affected by its forming 

 part of the plant-regime. Suppose we study under the microscope the 

 nature of the protoplasm which is locked up within the " cells " of 

 such plant-organisms as Chara, Tradescantia (Fig. 21), andVallisneria, 

 or within the cells comprising the stinging hair of the nettle's leaf. We 

 may readily see that active and incessant motion is the attribute of 

 the imprisoned living matter of the plant-cells. Ceaseless currents 

 of particles agitate the plant-protoplasm, which, but for the insidious 

 operation of " osmosis," whereby fluids pass in and out of the cells, 



would seem to be literally shut out 

 from all participation in outward 

 or external affairs. The cell of the 

 leaf-hair of Tradescantia (Fig. 21), 

 for instance, exhibits an incessant 

 flow of protoplasmic granules 

 hurrying steadily in definite direc- 

 tions, like the ordered traffic in 

 the streets of a great city. Stream 

 of protoplasmic currents unites 

 with stream, and ceaseless muta- 

 tion of the contents of the cell 



the result. In the nettle-hair the same phenomenon meets the 

 gaze of the microscopist. Here we find the same protoplasmic 

 substance lining the woody matter that forms the external wall of 

 the cell. Constantly does this living lining alter and change its 

 shape with wave-like contractions of its substance, and the granules 

 which exist in the fluid contents of the cell, hurry in various directions 

 with the same activity that we remarked in the cell of Tradescantia. 

 We thus awaken to the fact that in the seemingly inert and uncon- 

 scious field of plant-life there is activity enough, if we may but fortify 

 our seeing powers with the microscope, and peer awhile into the inner 

 recesses, and into the nooks and crannies of the vegetable world. 



Nor may we neglect to note in passing that, upon some higher 

 development of this same protoplasmic sensitiveness and activity 

 than is usual and common in vegetables, the marked powers of 

 sensation of such plants as the Venus's fly-trap and the Sensitive 

 Plants must depend. Locked up within the hard cell-wall, which, 

 as a rule, it is the business of plant-growth as distinguished from 

 animal increase to develop, there is little wonder that we have 

 come to regard the plant as an organism which feels not, and 

 which is apparently as destitute of all sensation as the world of 

 inorganic things. But the deeper view of plant-existence shows 

 us the fallacy of the common notion regarding the non-sensitiveness 



FIG. 21. Cell of a plant, (Tradescantia), 



drawn at intervals,_ and showing changes in 



the contained protoplasm. 



IS 



