NUCLEAR OSMOSIS AS A FACTOR IN MITOSIS. 157 
of the nuclear vacuole. It is believed that the karyolymph gradually diffuses by 
exosmosis into the cytoplasm. 
Throughout the entire prophase the nuclear membrane is functional in this osmotic 
transfer. 
As the nuclear vacuole becomes smaller and smaller, the membrane gradually 
closes in about the chromosomes. These latter become crowded together about the 
nucleolus. 
When the karyolymph becomes so much reduced that it is no longer visible as a 
clear nuclear sap, the membrane becomes closely applied to, and completely envelops, 
the surface of each chromosome. 
The result is that, instead of a single osmotic system represented in the nucleus, we 
now have established as many independent osmotic systems as there are chromosomes. 
For some time previous to the diffusion of the karyolymph the nuclear vacuole 
occupies a space that may approach or even exceed half the volume of the cell- 
eavity. So that all of these circumstances bring about a condition where a limited 
amount of cytoplasm of reticulate structure is obliged to occupy a cubical space which 
has greatly increased by the reduction in the volume of the nuclear vacuole. 
This necessarily sets up a tension in the cell 
adjustment and changed configuration in the reticulate form of the cytoplasm. 
As the nuclear vacuole becomes smaller and smaller, the cytoplasm in the region of 
the nuclear membrane becomes changed to the form of fine threads or fibrils which are 
drawn out from the reticulum by the receding membrane. 
The state of tension set up in the cytoplasm thus finds an expression in these drawn- 
out threads of ‘“ kinoplasm.” 
a tension sufficient to cause a re- 
From the different plants studied it seems that the lines of tension as expressed 
in the fibrils may group themselves in various ways at first. Thus we may have a 
weft of kinoplasm surrounding the nucleus; or a system of kinoplasmic radiations ; or, 
more commonly, a number of conical-shaped sheaves of fibrils. 
But whichever form the kinoplasm may appear to take, the lines of tension are 
constantly shifting throughout the prophase. 
Such a shifting does not mean the changing of the threads bodily from one position 
to another. It means the relaxing of the tension along certain threads, which would 
consequently fall back into the reticulum form, and the setting up of new lines of 
tension by the drawing out of threads from the hitherto undifferentiated reticulum. 
In this fashion not only individual threads, but entire sheaves or cones of fibrils 
may appear to assume different positions. 
For these and other reasons the generally accepted view that the sheaves or cones 
of fibrils in the multipolar figure approach one another and eventually coalesce into 
two groups should no longer be retained. 
There was no evidence to support the generally accepted view that the spindie 
fibrils grow into the nuclear area and attach themselves to the chromosomes, 
