130 Historical and Critical Considerations 



division is the only way in which the chromatophores are 

 newly formed/ Following up this idea with the phanero- 

 gams, Schimper discovered the colorless organs of the 

 youthful cells, which in these cells are exclusively charged 

 with the formation of starch and through whose assump- 

 tion of green color the real chlorophyll grains are formed. 

 In all cases that have been observed those amyloplasts 

 multiply only through division, and Schimper, as well as 

 Arthur Meyer, has accumulated such a number of obser- 

 vations on this manner of development that the former 

 view has been abandoned by all botanists. Some special 

 cases, it is true, still await explanation, but as long as 

 they have not been thoroughly investigated, there is no 

 reason for regarding the old conception more plausible 

 than the new one. 



It is similar with reference to the vacuoles. Until 

 about four years ago they were generally regarded as a 

 new formation in the protoplasm, caused by the secre- 

 tion of superfluous water of imbibition. In my "Plas- 

 molyfische Studien iiber die Wand der Vacuolen" I have 

 established the claim that, for them as well, the mode 

 of origin of nucleus and trophoplast^ must be the only 

 real one.^ I supported this claim by showing that all 

 vacuoles are surrounded by a living wall, which, accord- 

 ing to the method suggested by me, can always be easily 

 and convincingly demonstrated, and which I believe may 

 be regarded as an organ of the protoplast, with as much 

 right as the nuclei and the chromatophores. 



This conclusion, drawn from my panmeristic concep- 

 tion of cell-division, has been completely confirmed by 



'^Schmitz, F. Die Chromatophoren der Algen. Bonn, 1882. 

 ^By this name Arthur Meyer designates the amyloplasts and 

 their derivatives (chlorophyll grains, chromoplasts, etc.) 

 ^Jahrh. Wiss. Bot. 16: 489-505. 1885. 



