IRON COMPOUNDS IN ANIMAL AND VEGETABLE CELLS, 2138 
ments became thinner and less rich in chromatin, is more 
abundant. These nucleoli are eventually formed chiefly of 
chromatin, and in stained preparations appear to contain nearly 
all the chromatin of the nucleus. When mitosis again com- 
mences the filament forms at their expense, the increase in 
size of the filament keeping pace, apparently, with the decrease 
in the quantity of chromatin which the nucleoli contain. 
Finally, before their disappearance, when they contain but a 
minimal quantity of iron, they take the eosin stain deeply. 
All these forms of nucleoli take up safranin from solutions 
as readily as do the chromatin elements in the same nuclei, and 
they hold the stain as tenaciously when they are washed with 
alcohol. They are in this respect different from the eosino- 
philous nucleoli in the animal cell, which appear to be unrepre- 
sented in the vegetable cell. 
Of an exceptional character are the nucleoli in Corallo- 
rhiza multiflora and in Spirogyra. In these the greater 
portion of the chromatin in each nucleus forms a single large 
spherical element unconnected with the chromatin network, 
which after prolonged treatment with the glycerine and sul- 
phide mixture, gives a pronounced reaction for iron. 
I have, on a few occasions only, in preparations illustrating 
the iron reaction, seen the chromatin localised at points along 
the course of the filament, and concluded that this was not due 
to faulty methods of manipulation, for hematoxylin and other 
dyes just as infrequently render such a distribution visible. 
It was also, with the aid of the acid alcohols, found that in 
the loops of the mitotic nucleus of the embryo-sac the chro- 
matin is disposed under the membrane enclosing the filament, 
in such a way as to make the latter appear as a tube of 
chromatin. 
In some of the elongated oval nuclei of the nucellus and 
of the fibro-vascular bundle of the ovule, Mr. Bensley has 
observed a point of some interest. This consists in the occur- 
rence in the karyoplasm, amongst the trabecule of the 
chromatin network in one end of such a nucleus, of an iron- 
holding compound with all the characters of chromatin, and, 
