166 W. WALDEYER. 
salts, on the other hand, render them indistinct. Nearly all 
dyes—I mean those usually employed, such as acid-carmine, 
hematoxylin, saffranin—stain the network and the nucleoli 
very intensely, whilst the rest of the nucleus, the so-called 
“ nucleoplasm,” between the threads either remains unstained 
or takes only a very feeble stain. 
These differences in their behaviour tostains has led Flemming 
to distinguish in the nucleus so-called ‘chromatic substances” 
from “ achromatic substances.” Amongst the former he places 
the substance of the network and nucleoli which stains deeply 
and intensely by alum-carmine and anilin dyes; with the 
latter he places those parts which remain uncoloured, for 
example, what is spoken of as the ‘‘ spindle figure.” He calls 
the colourable substance of the network “ chromatin.” Re- 
lying on Zacharias’ researches he regards chromatin as perhaps 
identical with nuclein or with one of its derivatives.! 
The facts discovered by Balbiani (44) and Pfitzner (153) 
appear to be of some importance, viz. that the chromatic threads 
are composed of regularly arranged granules (spherules) of a tub- 
like shape,—“ discs” of Strasburger, ‘‘chromatin-spherules ” 
of Pfitzner, “‘ microsome-discs” of Strasburger (194) ; this is 
especially well seen during karyokinesis. It is now pretty 
generally admitted that, besides these ‘ chromatin bodies,” 
an achromatic intermediate substance, the ‘ nucleo-hyalo- 
plasma” of Strasburger, is present in the threads. Carnoy 
(47) believes that the single, greatly coiled chromatin thread 
present in the nucleus in Arthropoda has a “ plastin-envelope,” 
consisting of nuclein substances; this view is confirmed by 
1 Pfitzner goes still further in the use of the words chromatin and achro- 
matin. With Flemming he calls the colourable substance of the nuclear 
network “chromatin.” As the nucleoli behave somewhat differently to dyes 
and present other points of difference, he named their substance “ prochro- 
matin; by which would be implied that this was a first stage of chro- 
matin. Later, he selected the word ‘‘ pseudochromatin,” which does not 
indicate any definite connection with chromatin. For “nucleoplasm” he 
retains Flemming’s “achromatin;” giving, however, the name “ parachro- 
matin”’ to the substance of the spindle figure, which behaves differently from 
nucleoplasm. 
