232 PHYSIOLOGICAL BOTANY. 



tion, and Cell-development, wherein Schleiden's theory of 

 Phaneroganria is brought forward. In the second part 

 (1845), we find an appendix, entitled, Definition (Beyriff) 

 of .a cell. The author, after making some remarks upon 

 Schleiden's definition, says : " The idea of a cell signi- 

 fies that a portion of the organic matters becomes indi- 

 vidualised, invested with a membrane, by means of which 

 it is put in relation externally with the absorption and 

 exhalation of matters, whilst internally it undergoes 

 chemical and plastic changes." The commencement is 

 perfectly correct ; the idea of a cell signifies that a por- 

 tion of the organic matters becomes individualised, so 

 that the solid parts form externally an envelope, within 

 which, in part at least, matters exist in a fluid or even 

 in a gaseous state. Whether in all cells a solid body is 

 first formed, does not appertain to the idea, nor has this 

 been proved to be the case by observation. The nucleus 

 of the cell, as it appears to me and to others, is an irre- 

 gular accumulation of granules or vesicles, and seems 

 more like the mere commencement of a formation, than 

 a primitive formation itself, which here, as in almost every 

 other case originates in a liquid. The author says, with 

 perfect truth, the idea of an organism combines two im- 

 portant forces that by which it lives, and that by which 

 it propagates itself. But when it is added, that both of 

 these depend upon its being composed of cells, this 

 dependence certainly is not apparent. If it is proved 

 that the motion of Browne's molecules depends upon 

 an internal influence, they are alive, whatever may 

 be their internal structure. The organism requires a 

 reciprocal action of the parts upon each other as organs, 

 which is certainly most easily produced by the movement 

 of fluids within them ; but it by no means follows, it is 

 not proved, nay, it is opposed to experience, that it is 

 entirely composed of cells. If it were stated that it is 

 produced from cells, my reply would be, that this is very 

 probable, but nothing more. 



In the search for definition of a plant and of the 

 vegetable kingdom, much dependence is placed upon the 



