792 Kemp.—On the Question of the Occurrence of 
and binuclear cells are fewer in number, and also occur at a greater distance 
from the growing point. It would seem, therefore, that these cells are either 
gradually passing over into the permanent tissue, beyond the active region 
of the root-tip, or are breaking down one by one into masses of dis¬ 
organized chromatin, which masses are probably then absorbed by the sur¬ 
rounding tissue. 
In none of the experiments performed on bean roots were any figures 
found which could be interpreted as arising through heterotype reduction. 
Summary of the Results obtained with Vicia Faba. 
It will be seen from the above details that the action of the chloral 
hydrate is of the same nature in the case of the bean as in that of Galtonia. 
Its immediate effects are observable in swelling of the cell walls, shrinkage 
and vacuolization of the cytoplasm, disappearance of the achromatic fibres, 
and a certain alteration in the consistency of the chromatin. These features 
pass off with recovery of the tissue during subsequent growth ; and the net 
visible result of the action of the poison, apart from enhanced activity of the 
nucleoli, remains in the structural modifications which have arisen secon¬ 
darily in certain individual cells, and which persist for a considerable time. 
These modifications are due to the tetraploid condition induced by the 
imperfect mitoses which have taken place in such cells, owing to their lack 
of achromatic fibres. They are seen in figures of nuclei of abnormal shape 
and size, which, in diaster, are found to contain the tetraploid number 
of chromosomes, and which occur in cells of unusual dimensions and often 
peculiar orientation. 
As in the case of Galtonia , no ‘ heterotypical ’ figures are found in the 
bean. Consequently the evidence obtainable from this plant on the ques¬ 
tion at issue, namely the occurrence of heterotypical reduction in somatic 
cells, consists in the data which it affords as to the fate of the tetraploid 
cells. This evidence will be discussed later ; it may however be noted here 
that the numerous figures of multipolar division, and nuclear fragmentation, 
described above, seem to be sufficient to account for the disappearance of 
these cells without resorting to a hypothesis so difficult of proof as is that 
brought forward by Nemec. 
The chief points in the results obtained with the bean, which distinguish 
it from Galtonia , are the occurrence of multipolar division figures, and the 
comparative absence of those showing fragmentation of the large nuclei 
into numerous smaller ones. The second point is probably partly dependent 
on the first; fragmentation occurring less frequently in the bean owing to 
the greater opportunity of otherwise restoring the normal amount of 
chromatin, afforded by the above multipolar divisions. It may be added 
that considerable interest attaches to the latter owing to their close similarity 
to certain types of division seen in pathological growths. 
