82 Hypothesis of Structure of Germ Substance 
little discs of chromatin of the chromatic filament, in 
exactly the same disposition as that which these little 
discs actually do present in the chromatic filament. 
Admitting then that nuclear division is always quali- 
tatively equal we must now ask: does this really mean 
that the nuclei of all cells must remain alike throughout 
the whole of development? 
But before taking up this question we must first 
answer a preliminary one: must we exclude nuclear som- 
atization with the epigenesists or admit it with the pre- 
formists ? 
If it seemed to us impossible to disagree with the 
epigenesists upon the first question of a qualitatively equal 
nuclear division, it seems on the contrary impossible to 
disagree with the preformists on this second of a nuclear 
somatization. We shall certainly not repeat here all the 
arguments by which these latter support their thesis. 
They can be summed up in their essential parts in the 
following words of Weismann. 
“The chromatin is able to imprint upon the cell in 
the nucleus of which it lies a specific character. Just as 
the thousands of cells which make up the organism 
possess very different characters and very different 
functions, so the chromatin which controls them cannot 
be every where alike, but must rather be different in 
different kinds of cells.” 5? 
The epigenesists, on the contrary, are well known 
to be inclined to the view that all the somatic cells of 
the organism have, without distinction, like nuclei con- 
stituted by the same idioplasm. Oscar Hertwig indeed 
ventures the assertion that each somatic cell if it were 
“Weismann: Das Keimplasma, eine Theorie der Vererbung. 
Jena, Fischer, 1892. P. 43 and 268. 
