Relation between Nucleolus and Chromosomes. 61 
quite certain that the nucleoli do not contribute to the formation of the 
chromosomes and that their substance represents passive material, which is 
of no further direct use.’ On the ground that in Echinus he found the 
large vacuole of the nucleolus contractile, he regarded the latter as an excre- 
tory organ collecting the by-products of nuclear activity. 
E. B. Wilson (1896), agreeing with the conclusion of Hacker, states his 
opinion “ that the nucleoli of the germ-cells are accumulations of by-products 
of the nuclear action, derived from the chromatin either by direct transforma- 
tion of its substance or as chemical cleavage products, or secretions.” 
Certain observers, notably Flemming, O. and R. Hertwig, and Carnoy, 
regard the nucleoli as storehouses of material—paranuclein and plastin— 
which plays an active role in nuclear activity in contributing to the forma- 
tion of chromosomes during division. Strasburger (1895) considers the 
nucleoli storehouses of active material which he calls “ kinoplasm,” and which 
he thinks gives rise to the achromatic part of the division figure, Hauts- 
chicht, membrane, and cilia. 
Montgomery (1899), in his masterly work, “ Comparative Cytological 
studies, etc.,” gives a very complete review of the literature on the nucleolus. 
As the result of his own observation he is led to consider the nucleoli of egg- 
cells and somatic cells in the Metazoa as homologous cell organs. He regards 
the nucleoli “as extranuclear in origin, and not a secretion or excretion 
of the nuclei . . . consisting of a substance or different substances, 
taken into the nucleus from the cell-body.” He thinks it probable that 
“these substances stand in some relation to the nutritive process of the 
nucleus.” 
According to Fick (1899) the nucleolus is simply a storehouse or labor- 
atory of nuclein. Bryce (1903) combines the views of Strasburger and Fick 
in regard to the nucleolus in Echinus esculentus. 
My study of the nucleolus (germinal spot) in the egg of Asterias forbesii, 
both in the living and fixed condition, yields no evidence in support of 
either Hacker’s “ Kernsecret-theorie” or Strasburger’s “kinoplasmic” theory. 
Nor do my results accord with the view of Bryce in so far as he adds 
the “kinoplasmic” to the “storehouse” theory, to explain the nucleolar 
function in Echinus. The evidence above given is conclusive, I believe, that 
in Asterias the nucleolus is a storehouse of reserve chromatin. This is 
demonstrated to be true by the fact that just previous to maturation connec- 
tions are established by virtue of which chromatin material passes from the 
nucleolus to the chromosomes and in consequence of which the latter grow 
in size. In view of the fact that the chromosomes never really enter the 
nucleolus, it is very doubtful whether any “ idioplasm,” as Rhumbler believes, 
is stored in the nucleolus. I believe that all the hereditary elements are per- 
sistently held by the chromosomes whatever their various size and form 
throughout the growth-period of the eggs, and that these merely receive 
