26 



a corpuscle may be found containing a dark violet-red spot in 

 the same situation as the spots coloured by methylene-blue. I 

 stained the material, killed with formol-alcohol, also with haema- 

 toxyline, just as Brandt did; theij the oil-drops appeared to be 

 coloured somewhat violet — in this case not by concentration 

 of the light in the field of the microscope — , while sometimes 

 chlorophyll corpuscles were te be found containing a violet spot 

 in the same place, where it was in the other stainings. But 

 there were also specimina containing numerous spots, even irre- 

 gular violet lines (Fig. 42). The same result was obtained by 

 staining of the material (with haematoxyline) when killed with 

 Zenker's liquid. 



These results prove, that it is not impossible that those more 

 diffuse, centrally situated, little spots are real nuclei. Against this 

 view, however, speaks the following : 1. these spots were but 

 seldom to be found in a corpuscle; 2. in other cases the cor- 

 puscle contained numerous of those spots and even irregular lines 

 with exactly the same (violet) colouring. One might rather think 

 them to be accidental colourings of arbitrary enclosures of the 

 protoplasm (conf. the oildrops). Consequently, I do not venture 

 to settle the question of the presence of a nucleus in the chloro- 

 phyll corpuscles. 



When now we compare my results with those of Brandt, 

 there is very much conformity in the facts stated ; and only a 

 difference on the chief point of the frequency with which the 

 so called nuclei occur. Brandt found them in all corpuscles. 

 Now I suppose that Brandt, who never mentions the oildrops 

 in the corpuscles, evidently does not know them, simply has 

 always considered these also somewhat violet coloured oildrops as 

 nuclei, as well as the diffuse spots. In this way it is possible 

 that he found all corpuscles containing a nucleus. 



4. The cell-wall. Only one decisive way exists for demonstrating 

 a cell- wall : by means of plasmolysis. I therefore put the isolated 

 green corpuscles for many hours into a solution, which I had acci- 

 dentally at hand, viz. that of pag. 10, I (inorg., in concentration X 

 50). The plasmolysis could be observed very distinctly on many 



