288 West and Lee timere>—On Chromatin Extrusion in 
into the cytoplasm of a single mother-cell, was frequently found ; Gates’s 
(10) (1. c., p. 917) explanation that this is due to the complete absence 
of cytoplasmic connexions between the pollen mother-cells and the cells of 
the tapetum is probably correct. 
R6le of the Nucleolus. 
Apart from the behaviour of the nucleolus, the descriptions of 
‘ chromatin ’ extrusion in Galtonia and Oenothera respectively show a close 
agreement. In Galtonia , active nucleolar budding is described by Miss 
Digby; in Oenothera , on the other hand, the nucleolus, according to Gates, 
takes no part in the extrusion. For this reason, the behaviour of the 
nucleolus in Lilium candidum was studied with special care ; we were 
nevertheless led to the conclusion that it takes no part whatever in the pro¬ 
cess under discussion. That is to say, during the various synaptic phases 
the nucleolus (or nucleoli, since two are occasionally found in the same 
nucleus) retains its definite boat-shaped or spindle-shaped outline. Vacuoles 
were sometimes noticed in the substance of the nucleolus (Figs. 1 and 4), 
but no sign of nucleolar budding was observed. 
Discussion. 
Kornicke ( 14 ) described the peculiar appearances presented by a 
number of preparations of Crocus vernus . A definite extrusion of chro¬ 
matic substance from the pollen mother-cell nucleus and its passage through 
the cell-wall into the cytoplasm of an adjacent mother-cell were observed. 
Kornicke attributed this phenomenon to an abnormal condition of the 
anther at the time of fixation, and states ( 1 . c., p. 24): 4 Am wahrschein- 
lichsten ist, wie ich glaube, die Annahme, dass es sich um den Ausdruck 
einer Alteration handelt, welche die Pollenmutterzellen erlitten haben bevor 
die Antheren den jungen Bliitenanlagen entnommen wurden, und deren 
Ursache auf folgende Bedingungen zuriickzufuhren ist, unter welchen sich 
die Antheren in der Pflanze befanden/ He maintains that the release of 
pressure on artificially opening the bud, which to a certain extent com¬ 
presses the anthers, may allow a sudden expansion of the latter whereby 
the protoplasmic connexions between the pollen mother-cells are broken. 
In this way a slight wound stimulus is given to the cells. 
The interesting experiments ofMiehe ( 15 ), Hottes ( 13 ), and Schrammen 
( 19 ) may be quoted in support of this hypothesis. Miehe clearly showed 
that a transference of nuclear material from one cell to an adjacent cell can 
take place as a direct response to certain traumatic stimuli. He figures 
( 1 . c., Taf. xi, Figs. 2 and 3) such a process in epidermal cells of a young leaf 
of Allium nutans . But the fact that Miehe obtained his results in typical 
vegetative cells, the nuclei of which were probably in the 4 resting ’ con¬ 
dition, must be taken into account when the two processes are compared. 
