1038 



add that this picture is the only one among my extensive material 

 in which I found such far advanced incisions in the nuclei, these 

 facts certainly support the idea tliat there really are natural forma- 

 tions. All these cells that show signs of amitotic division are very 

 young. Some of them have no signs at all of processes (fig. 19 and 

 bo), while others show indications of the beginning of a develop- 

 ment of these (tigs. 96, 16, 17, 18, and 21). I can agree with Pala- 

 DiNo's statement quoted above that it is only before the differentia- 

 tion of the processes that amitotic division takes place. On the strength 

 of the appearances in this material I am of the opinion that the 

 amitotic division proceeds in the way : 



a) The nucleolus') increases in length and begins to show incisions 

 in the middle ; this incision becomes deeper and deeper (figs 16 and 

 17) and finally we have a division into two nucleoli, each of which 

 moves to an end of the nucleus of the cell, which has begun to 

 become drawn out into a more or less oval formation. The nucleoli 

 often exhibit a continued power of generation even after they have 

 moved out to the future daughter-nuclei; it is this that causes us 

 often to see in such daughter-nuclei either one nucleolus engaged 

 in direct division or else several nuclei, a number of which may 

 be seen moving out of the nucleus. I have not been able to decide 

 with certainty whether the filaments (nuclear fibres) of the nucleus 

 thereby have any specific function. It is a fact, however, that there 

 are sometimes appearances which point to this being i-eally the case 

 (fig. 16 and 17). h) The drawn-out, elliptical nucleus begins to show 

 signs of incision in the middle (fig. 16, 17, and 18). This incision 

 usually takes place in the middle, so that the two daughter-nuclei 

 are equally large. There are, however' figures showing the existence 

 of a slight dissymmetry (fig. 18). The incision grows deeper, but is 

 not as a rule, however, deeper than is shown in fig. 20, the con- 

 nection between the nuclei being retained. Incision of the nuclei as 

 far advanced as that shown in figs. 9b and 21 is exceedingly infre- 

 quent and these figures are the only ones I found of this type. 

 There are also figures that indicate that the fibres of the nucleus 

 may have something to do with the division of the nucleus, c) If 

 the cell in which the nucleus divides amitotically is at a very early 

 stage of development, a cleavage of the protoplasm does not, in 

 most cases, ensue, but a cell plasmodinm arises. These cells are 



') It should, however, be noted that such phenomena of new growth often appear 

 in the nucleoli without the nucleus otherwise showing any signs of an amitotic 

 division. 



