MOTION IN PLANTS. 341 



complete if it were to omit a consideration of these forces, and 

 of the substances which enter into sohd and fluid combina- 

 tions in organic tissues, under conditions which, from our igno- 

 rance of their actual nature, we designate by the vague terra 

 of vital forces, and group into various systems, in accordance 

 with more or less perfectly conceived analogies. The nat- 

 ural tendency of the human mind involuntarily prompts us 

 to follow the physical phenomena of the Earth, through all 

 their varied series, until we reach the final stage of the mor- 

 phological evolution of vegetable forms, and the self-determin- 

 ing powers of motion in animal organisms. And it is by these 

 links that the geography of wganic beings — of plants and 

 animals — is connected with the delineation of the inorganic 

 phenomena of our terrestrial globe. 



Without entering on the difficult question of sjiontaneous 

 motion, or, in other words, on the difference between vegeta- 

 ble and animal life, we would remark, that if nature had en- 

 dowed us with microscopic powers of vision, and the integu- 

 ments of plants had been rendered perfectly transparent to 

 our eyes, the vegetable world would present a very different 

 aspect from the apparent immobility and repose in which it 

 is now manifested to our senses. The interior portion of the 

 cellular structure of their organs is incessantly animated by 

 the most varied currents, either rotating, ascending and de- 

 scending, ramifying, and ever changing their direction, as 

 manifested in the motion of the granular mucus of marine 

 plants (Naiades, Characea3, HydrocharidsB), and in the hairs of 

 phanerogamic land plants ; in the molecular motion first dis- 

 covered by the illustrious botanist Robert Brown, and which 

 may be traced in the ultimate portions of every molecule of 

 matter, even when separated from the organ ; in the gyratorv 

 currents of the globules of cambium {cyclosis) circulating in 

 their peculiar vessels ; and, finally, in the singularly articula- 

 ted self-unrolling filamentous vessels in the antheridia of the 

 chara, and in the reproductive organs of liverworts and algae, 

 in the structural conditions of which Meyen, unhappily too 

 early lost to science, believed that he recognized an analogy 

 with the spermatozoa of the animal kingdom.* If to these 



* [" la certain parts, probably, of all plants, are found peculiar spiral 

 filaments, having a striking resemblance to the spermatozoa of animals. 

 They have been long known in the organs called the antheridia of 

 musses, Hepaticn", and Characea?, and have more recently been dis- 

 covered in peculiar cells on the germinal frond of ferns, and on the 

 very young leaves of the buds of^Phanerogamia. They are found in 

 peculiar cells, and when these are placed in water they are torn by the 



