204 Pangcns in the Nucleus and Cytoplasm 



compounds, secreted by the nucleus, should take place 

 through the plasm to the place of growth. The effective- 

 ness of these substances would doubtless be dependent on 

 the degree of cencentration of their solution, and this in 

 such a way that the cytoplasm would react to them only 

 at a certain concentration." 6 



But in order to react in a definite manner on the sub- 

 stance secreted by the nucleus, the cytoplasm must already 

 possess the requisite characters. Starch will react to a 

 secretion of diastase, but not all kinds of substratum will 

 do so. Thus the assumption of enzymatic effects demands 

 the presence, in the cytoplasm, of hereditary characters, 

 which have been taken from the nucleus. 



Therefore, no matter how strange the assumption of 

 a transmission of pangens from the nucleus to the cyto- 

 plasm may appear at first glance, we arrive by the most 

 various ways of reasoning at a recognition of its correct- 

 ness. 



An important question is that of the time when this 

 transportation chiefly occurs. A comparative considera- 

 tion of the various forms of variability will in the end, 

 it is hoped, furnish the necessary material for its answer ; 

 in the mean time we may assume it as probable that im- 

 mediately after fertilization, as well as during or after 

 every cell-division, such a transportation takes place. Hy- 

 brids, and those variations that affect in a similar man- 

 ner all the members of a plant, argue in favor of the first 

 point, and for the other, the previously discussed phenom- 

 ena of dichogeny, where during the earliest youth of an 

 organ its later nature can be determined by external in- 

 fluences. When, for instance, the terminal bud of a 

 rhizome grows prematurely and turns into an upward 



6 Haberlandt, G. Ueber die Beziehungen zwischen Function und 

 Lage des Zellkcrncs, p. 14, note. 1887. 



