DR. M. J. SCHLEIDEN ON PHYTOGBNESIS. 299 



{verwachsen, to grow together) has possessed however from time 

 immemorial, both in common Ufa and in science, the signification 

 that two or several originally and naturally separate parts have be- 

 come by the process of growth either abnormally, or, under cer- 

 tain circumstances regularly, united. If, therefore, we apply the 

 word "cohere" {verwachsen) to the stem of the plant, an organ, 

 which, in every period of its existence, under all forms of its ap- 

 pearance, is a simple and undivided one, and at the origin of the 

 plant even constantly makes its appearance earher than the leaves 

 with their petioles, there certainly is in this a monstrous misuse 

 of language, and science itself can gain nothing by it, and even 

 loses in the eye of the intelligent layman who sees through such 

 a play upon words. What would the zoologist say were we to 

 regard the trunk as a cohesion of the extremities ? 



But I come back to my question : What is To grow ? An old 

 twaddler says. To grow signifies increase of the mass of an indi- 

 vidual, and takes place in the inorganic Avorld by juxtaposition, 

 in the organic by intus-susception. Have we gained anything by 

 this for vegetable physiology ? I think not. If the plant is to 

 grow by intus-susception, then I say the plant consists of an ag- 

 gregate of single, independent, organic molecules, the cells ; it 

 increases its mass by new cells being deposited on those already 

 existing ; consequently by juxtaposition. But the single cells 

 in their expansion, frequently to an enormous bulk in compari- 

 son with their original size (I need merely call to mind the pol- 

 len tubes), also increase in substance in the interior of their 

 membrane, and in this way also the mass of the whole plant is 

 increased; it consequently grows by intus-susception also. Lastly, 

 the cell deposits after a certain time new organic matter in layers 

 upon its primitive membrane, therefore a juxtaposition again, 

 which still however belongs to the cycle of the life of the plant. 

 It is hence easily apparent that the idea « grow" still requires 

 for the purposes of scientific botany a new foundation in order 

 to be capable of being applied with certainty. 



Of the three above-named cases, the second and third belong 

 more to the individual fife of the cells, and are of secondary 

 importance only, as concerns the idea of the whole plant, re- 

 garded as an organism composed of a certain (1 to co ) num- 

 ber of cells. The plant considered in its totality increases its 

 mass, that is, the number of the cells composing it, in the first 

 way only. 



