168 Samuels. — A Pathological Anatomical Study of 
neighbouring cell with the nucleus of the young cyst, the nucleus of the 
latter displays a more or less round form. Later, it stretches lengthwise 
and takes a position along the wall, and indeed, most frequently, at one of 
the ends of the hypertrophied cell. Because of the abnormal regulatory 
processes in this condition of cyst development, the nucleus is pushed to 
one side. 
The fusion of the protoplasts reminds one of the normal fusion of 
living protoplasts or of the ontogeny of non-septated (36) and septated sieve 
tubes, and also of the processes of the sexual cell fusions. This is likewise 
true of normal fusion processes, found for example in the pith of the 
hypocotyl and epicotyl of the bean stem which has been treated with violet 
or diffused light, 1 and also of the cell fusion during the formation of secre- 
torial cysts and tubes. Cell fusion may finally take place after infection, as 
for example in the case of Hcterodera Schachtii (25). Kiister suggests that 
it is very difficult to decide whether the material which dissolves the cell 
wall is produced by the parasite or by the host cells themselves. In the 
crystal symplasts there occurs a similar solution of perforated or defective 
cell walls. The cell-wall dissolving material is after all probably produced 
in this case in the symplasts themselves. It is certainly more difficult to 
find the reason for the fusion of two parenchymatous cells with a young 
cyst cell, than to determine the cause of the fusion of two or more endo¬ 
sperm cells. Since it might be suggested that, in the latter case, 
there is a solution which is of enzymic nature and concerns the 
solution of reserve products, it is a matter of fact that, by the fusion of 
nuclei of other neighbouring cells with this hypertrophied nucleus, the latter 
becomes richer in water, and for that reason assumes its original form 
again. 
However, if the fusion ceases and the formation becomes more active, 
the combination with water begins again and also becomes more and 
more active; the nucleus, as a consequence, undergoes an elongation 
during which it takes various amoeboid and convoluted forms. Probably 
the increase in surface area of the nucleus enables it to absorb water mole¬ 
cules more freely at the proper time, so that it regains its original form. 
A circumstance in favour of this view is the fact that as a cell becomes older 
and approaches the end of its functional ability it becomes more devoid of 
water than before, particularly in cells of a secreting character such as 
those here discussed. In addition to the above suppositions relative 
to the withdrawal of water, other circumstances and factors may affect 
the change in form of the nucleus; The change in nuclear form in the 
calcium oxalate cyst reminds one of the change in nuclear form in the 
V 
1 Paper read at the meeting of the American Association for Advancement of Sciences in New 
York, 1916. 
