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Transactions of the Society. 
nucleus (idioplasm) contains especially the hereditary substances, 
which also possess the ability to generate a new somatic nucleus. 
In tissue-cells the separation may be quite unnoticeable ” ( 9 ). 
Various writers have sought to identify the chromosomes with 
the idioplasm, and the nucleolus with the kinoplasm. 
A certain amount of evidence has been accumulated in support 
of this view, and the nucleolus does appear to be related to 
nutrition ; but Dobell, who has written a review and summary of 
the theory, concludes that we “ require many, many more facts 
and unbiassed observations before we can hope to unravel the 
tangled skein ” of which this problem is but a part. 
In a recent paper in “ Science Progress,” 1921, Gatenby has 
brought forward the view that the nucleolus represents not the 
kinoplasm but the trophoplasm or trophochromatin. 
(iv.) Germ-Cell Determinants . — Both Silvestri (S3) and Haecker 
{20) have suggested, probably erroneously, that the nucleolus may 
function as a germ-cell determinant. Very little work, however, 
has been carried out on this aspect of the subject, and there is 
great need for more information before drawing conclusions. 
(v.) Chromatin Theories. — There has been a considerable 
amount of discussion as to the relation of the nucleolus to the 
chromosomes. Strasburger (56) believed that in the somatic 
nuclei of many plant cells most of the chromatinic substance was 
stored in the nucleolus, while Schaxel (50) held the same view 
with regard to the nucleolus of the oocyte of Echinus. It is 
generally agreed now that the nuclear network gives rise to all 
the chromosomes. In this connexion Sharp (4-8) writes, “ Although 
the nucleolus furnishes no morphological element, chromatic 
material may flow from it to the chromosomes as they develop 
from the reticulum.” He cites as evidence the work of Strasburger 
and Berghs (48) on Marsilia. 
I have suggested elsewhere that the basophil nucleolus found 
in the oocytes of Molluscs may be related to the contraction of 
the large nuclear reticulum to form the chromosomes. According 
to Sharp, Eisen does not consider the nucleolus has anything to 
do with the chromosomes in so far as their idioplasmic constitu- 
tion is concerned, but he regards the nucleolar material as a reserve 
constituent of the linin reticulum. Schurhoff (52), on the other 
hand, regards it as a reserve constituent of the chromatin. 
(vi.) Cell-Division Theories . — The observations of Remak and 
others upon the behaviour of the nucleolus during amitotic nuclear 
division, led to the conclusion that this organ played an important 
part in cell division. In certain cases of amitosis, the nucleolus 
divides previously to nuclear division. From this it was assumed 
by some workers that the nucleolus actually initiated the division 
of the nucleus. Since however this type of cell division was first 
described, it has been found to be extremely rare, and in some 
