172> DR. E, KLEIN. 



POSTSCRIPT. 



The foregoing paper was in print when Professor Flem- 

 ming's last memoir — " Contributions to the Knowledge of 

 Cells, &c." — appeared in the ' Archiv f. Mikrosk. Anat.,' 

 Band xvi^ p. 302. This memoir, which is of considerable 

 length, records many important observations regarding the 

 structure of cells and nuclei and the phenomena of cell- 

 division. 



Flemming's views on the structure of cells and nuclei, and 

 the relation of the two, do not in some respects coincide 

 with those expressed by me in Part I of this paper (see this 

 Journal, Vol. XVIII, p. 315), and also in the present Part II. 

 It is not possible for me to enter here into a detailed 

 discussion of those differences, for the reason that this im- 

 portant subject could not receive full justice in a short para- 

 graph, and chiefly because, in the third and concluding part 

 of this paper, I shall have opportunity to return to the sub- 

 ject. But 1 will at once here state my dissent from Flemming 

 in two important points : 



a. Professor Flemming, on p, 335, says that the network 

 that I described (in Part I of my paper) of the nuclei of 

 stomach and mesentery of newt, after treatment with 5 per 

 cent, chromate of ammonia, does not quite correspond to the 

 network seen by him in the nuclei of Salamandra in the 

 fresh state, and is therefore, in its totality, not to be regarded 

 as a preformed structure. 



Oa the same page (335) he also says that the nuclei delineated in many 

 of my figures (see Plate XVI of this Journal, July, 1878), are knobbed 

 and distorted, and this he regards as additional proof for his above state- 

 ment. I see from this that Professor Pleniming has looked at my figures 

 and read my text with only passing attention, for in that Plate (XVI) I 

 have delineated, and in the text I have described, the nuclei as oval sharply 

 outlined structures, with a smooth surface. Of a knobbed or distorted 

 state I have figured or said nothing. In a very few instances the nucleus 

 is slightly knobbed, e.ff. in the dividing nucleus of unstriped muscle fibres 

 of the mesentery of newt (1. c, p. 332). ■ I also find that Professor Flem- 

 ming describes (on pages 307 and 319 of his memoir) a similar condition of 

 nuclei of developing Salamandra in the perfectly fresh and living state. 



h. As far as I am able to understand Professor Flemming's 

 observations and arguments on the structure of the nucleus 

 during life and after reagents, it comes to this, that during 

 life some nuclei show nothing of a network or of anything 

 else, being in some instances not visible at all; others show 

 a network more or less imperfectly, with dots and large par- 



