He finds that eight chromosomes appear in karyokinesis in the ordinary thallus cells, but sixteen in the gonimoblast filaments derived from the fertilized carpogonium.
And this is all that the facts of karyokinesis prove.
The facts of karyokinesisare generally claimed by the school of Weismann as making exclusively in favour of continuity as absolute.
We shall also see how it is {xv} possible by simple liquid diffusion to reproduce in ordered and regular succession complicated movements like those observed in the karyokinesis of the living cell.
For instance, in the diffusion preparation we notice at each extremity of the equator a V-shaped figure with its apex towards the centre, corresponding exactly to what in natural karyokinesis is called the equatorial crown.
If in the saline solution we place a coloured isotonic drop between two coloured hypertonic drops, all the figures and movements of karyokinesis appear successively in their due order.
Guided by this theory of a diffusion field of force, I have been able to reproduce experimentally the figures of karyokinesis by simple diffusion.
This phenomenon, namely the production ofkaryokinesis from centres of catabolism, may account for the abnormal karyokinesis of cancer cells and the like.
In this case, however, the resemblance to natural karyokinesis is less perfect.
The resemblance of these successive phenomena to those of natural karyokinesis is of the closest.
Other phenomena ofkaryokinesis may also be closely imitated by diffusion.
In the process of karyokinesis the two centrosomes, i.
Many of these so-called explanations are mechanical, while others invoke the aid of magnetism or electricity to account for the resemblance of the figures of karyokinesis to the magnetic or electric phantom or spectre.
It may be employed to study karyokinesis in the cells of a rapidly growing cancer.
This interpretation of ordinary karyokinesis is less uncertain than perhaps at first sight it may appear to be.
Platner[268], in his excellent paper on karyokinesis in Lepidoptera, also points out that the karyokinesis of the spermatocytes is essentially different from that of the spermatogonia.
There must be two kinds of karyokinesis according to the different physiological effect of the process.
Until this point is settled, we cannot decide with certainty whether the described form of karyokinesis is to be considered as the ‘reducing division’ for which we are seeking.
On the other hand, the form of karyokinesis in which a longitudinal splitting of the loops takes place before they separate to form the daughter-nuclei must always, as far as I can see, be considered as an ‘equal division.
Now there is more evidence for the existence of this second kind of karyokinesis than the fact that it is demanded by my theory; for I believe that it has been already observed, although it has not been interpreted in this sense.
Karyokinesis of a typical tissue-cell (epithelium of Salamander).
As a matter of fact, in many cases of tissue-formation karyokinesis has not hitherto been detected.
The first is, that in some of the Protozoa processes very much resembling those of karyokinesis have already been observed taking place in the nucleus preparatory to its division.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "karyokinesis" in a variety of sentences. We hope that you will now be able to make sentences using this word.
