in Lilium Mar tag on: II. Spermatogenesis. 193 
siderable quantity of amorphous chromatin is still present 
when the nuclei have completed their growth in size, and 
even when indications begin to appear of the approach 
of synapsis. 
The passage from the resting-state to the contracted con- 
dition known as synapsis is very instructive in these nuclei. 
No independent evidence of the seriation of stages could be 
obtained from preparations of the corresponding period in the 
embryo-sac. The comparative ages of the nuclei, where 
the difference was slight, were settled on internal evidence 
only. But in a single longitudinal section from a young 
anther, the pollen-mother-cell nuclei at one end may be in the 
late resting-condition, while those at the other are completely 
contracted. The intermediate nuclei then exhibit an orderly 
series of transitional forms. 
The approach of synapsis is first indicated by the appear- 
ance of drops of nucleolar matter adhering to the chromatic 
network. The larger of these drops can be identified by their 
reddish colour in sections from alcohol-material stained with 
methyl-green and acid fuchsin. The nucleoli are still spherical 
and well defined, but often vacuolated. A little later the 
nucleoli lose their well-defined outline, the nuclear membrane 
becomes indistinct, and the chromatic threads show a tendency 
to collect round the nucleoli at one side of the nuclear cavity 
(Fig. 2). This contraction becomes more and more pro- 
nounced, the nucleoli collect into a shapeless mass of ill-marked 
outline, and the nuclear membrane seems to have disappeared 
as a continuous structure. Its place is taken by a sort of web 
of cytoplasmic fibrils. In sections stained with methyl-green 
and acid fuchsin it is to be remarked that the nucleolar mass 
is often coloured green in the thicker parts — as, for example, 
near x in Fig. 2. Possibly it has dissolved the amorphous 
chromatin which was still visible in the later stages of the 
resting-nucleus. The edges of this greenish mass are always 
of a washy-red colour, and the nuclear sap in its neighbour- 
hood is clouded with red. 
Even in such a preparation as that from which Fig. 2 is 
