503 
in the Hymenomycetes. 
irregular, and presents a characteristic appearance (Fig. 17). 
Soon, however, a faintly-stained network appears. This 
becomes more and more distinct and stains deep blue. The 
outline of each nucleus becomes more regular, and finally the 
two nuclei arrive at the stage in which they in every way 
resemble the parent nucleus. The two nuclei thus formed 
are placed side by side at the apex of the basidium, and take 
up nearly the whole of its diameter (Fig. 19). 
As the daughter-nuclei gradually increase in size and 
assume the form and structure of the parent nucleus, the 
nucleoli also become larger, and both nucleoli and network 
soon have the same capacity for staining as in the parent 
nucleus. At the same time the protoplasm loses its capacity 
for intense staining. It is probable, therefore, that the increase 
in size of the nucleolus is due to the absorption by it of 
nucleolar substance from the cytoplasm. 
Behaviour of the Nuclei towards the Red and 
Blue Stains. 
The changes which take place in the nucleolus and chro- 
matic elements, as regards their capacity for taking up the 
red and blue stains, are very interesting, especially in the 
light of the recent researches of Auerbach 1 , Schottlander 2 , 
Rosen 3 , Strasburger 4 , and Zacharias 5 , upon this phenomenon. 
Moreover, they appear to me to throw some light upon the 
much-debated question of the nourishment of the chromatic 
elements by the dissolved nucleolar substance. In connexion 
with this question Went 6 has already pointed out that, on 
1 Ueber einen sexuellen Gegensatz in der Chromatophilie der Keimsubstanzen . 
Sitzungsber. der K. prenss. Akad der Wiss. zu Berlin, 1891. 
2 Beitrage zur Kenntniss des Zellkerns und der Sexualzellen bei Kryptogamen. 
Cohn’s Beitrage zur Biologie der Pflanzen, Bd. VI, 1892. 
3 Beitrage zur Kenntniss der Pflanzenzellen I. Cohn’s Beitrage zur Biologie der 
Pflanzen, Bd. VI, 1892. 
4 Ueber das Verhalten des Pollens, &c., Hist. Beitrage, Heft iv, 1892. 
5 Ueber Chromatophilie. Ber. d. Deutsch. Bot. Gesells. Bd. XI, 1893. 
6 Went, Beobachtungen uber Kern- und Zelltheilung, Berichte d. Deutsch. Bot. 
Gesells. 1887. 
