158 Aittoiioiny of Cell-Organs 



plasm and the wall of the vacuole, or whether they stand 

 in the same genetic relation as amyloplasts and chloro- 

 phyll-grains. As long as this question remains undecided, 

 the application of my hypothesis to the plasmatic mem- 

 brane and therewith to the surface growth of the cell- 

 membrane and all the formative processes of the cells, 

 is rendered very difficult. For this reason may I be 

 "allowed to subject the respective phenomena to a critical 

 revision in order to encourage further research. I think 

 it will then be seen that the prevailing opinion that the 

 plasmatic membrane originates in every case from the 

 granular plasm is, for the present, not supported by cer- 

 tain and closely observed facts, but is adhered to only 

 from habit. This, however, it seems to me, ought not 

 to be allowed in view of the newer knowledge in regard 

 to the origin of the wall of the vacuole. For, as long as 

 no special wall was assumed for the vacuoles, it was nat- 

 ural not to regard the plasmatic membrane as a special 

 organ. Since the independence of the former has been 

 established, such is obviously most probably the case for 

 the latter also.^^ 



Besides the incompleteness of the observations, which 

 is to be demonstrated in the next paragraph, the whole 

 course of the development of our knowledge in the field of 

 cell-anatomy on the one hand, and the already repeatedly 

 described differentiations of the plasmatic membrane and 

 the granular plasm on the other hand, controvert the 

 prevailing opinion. The latter does not form at all, as 



^^A method by which the plasmatic membrane could be arti- 

 ficially separated everywhere from the granular plasm, just as strong 

 plasmolytic reagents separate the wall of the vacuole, is particu- 

 larly desirable. Such a method could also render great service in 

 judging the hypothesis mentioned on page 160, Note 2, on the growth 

 in thickness of the cell-membranes. 



