42 
THE ORGANIC CELL 
the egg, and also that the very marked development of the 
nucleus in these cells is correlated with this function. 
With regard to the position of the nucleus and the source 
of food supply, one most interesting case only will be mentioned, 
viz. that of the water-beetle Dytiscus in which Korschelt was 
able to watch the phenomena in the living form. The eggs 
lie alternating with nutritive cells. These nurse-cells contain 
granules which are believed to pass into the egg. That such 
is the case is all but evident from the fact that the egg contains 
quantities of similar granules, which are seen lying in masses 
extending from the nurse-cells right to the germinal vesicle, 
which they often envelop. The germinal vesicle (egg-nucleus) 
now assumes the function of amoeboid movement, and extends 
its false limbs always towards the mass of granules. 
The exceedingly rapid growth of the germinal vesicle at 
this period points to the conclusion that the granules are 
absorbed into its substance. 
All the observations made go to show that the nucleus of 
the cell plays an important part in the process of nutrition, 
and that it obtains a maximum activity during the phases which 
are characterised by greatly increased growth. It is therefore 
evident that, so far, the behaviour of the nucleus corroborates 
and is in harmony with the results obtained from experiments 
on one-celled forms. 
The Nucleus in Mitosis. 
W. Roux was the first to point out that ‘ the essential 
operation of nuclear division is the division of the mother- 
granules ’ (chromatin grains) ; ‘ all the other phenomena are 
for the purpose of transporting the daughter-granules derived 
from the division of a mother-granule, one to the centre of one 
of the daughter-cells, the other to the centre of the other.’ 
The cytoplasm, on the other hand, merely undergoes a mass 
division. 
The great central fact must be insisted on that the chromatin 
of the mother-cell is ‘ distributed with the most scrupulous 
equality to the nuclei of the daughter-cells,’ and that in this 
regard there is a most remarkable contrast between nucleus 
