CHROMIDIA AND THE BINUCLEARITY HYPOTHESES. 309 
nucleus (or its homologue the chromidial net!) plays no part 
in the vegetative life of the protozoan cell, as itis to maintain 
that the germ cells of a metazoan individual play no part in 
its general somatic metabolism. 
In that the nuclear conditions seen in Infusoria are 
specialised, and not primitive—to my mind—they show no 
more that the cell is by nature binucleate than a metazoan 
containing » different organs—each with its specialised nuclei 
—shows that the cell was originally by nature 7-nucleate. 
To say that the cell nucleus possesses the two distinct 
functions of growth and reproduction is a platitude. But to 
say that these two functions are restricted to special parts of 
the nuclear material is not warranted by the facts known to 
us at present. All the facts appear to me to point to the 
conclusion that growth and reproduction—somatic and propa- 
gative functions—are united in the same living nuclear 
molecule. One or other may come to preponderate, but that 
is the necessary result of cellular differentiation, 
I think a great deal of error has crept into the chromidial 
hypothesis of binuclearity through the unfortunate application, 
originally, of a similar name to two quite different things— 
the chromidia of Actinospherium (products of metabolism 
or disintegration) and the chromidial net of Thalamophora (a 
reproductive organ). When Goldschmidt added to these the 
chromidial apparatus of ascarids—again quite a different thing 
(cf. p.302)—confusion was complete,and hence the deductions 
which at first sight appear so legitimate. To my mind, the 
facts by no means allow of the conclusions drawn by 
Goldschmidt (p. 507). 
Starting from these—to me—false premises, Goldschmidt 
certain that the chromidium fulfils trophic functions” (Elpatiewsky, 
07). “ That there exist pure gametochromidia, entirely without admix- 
ture of somatic nuclear matter, is improbable ” (Schaudinn, ’05). 
1 Cf. Swarcewsky, 08. From his work it appears that in Arcella 
the chromidial net gives rise to secondary nuclei, which enter not only 
into the gametes but also into asexual buds; so that here at least there 
is no justification for regarding the chromidium as purely gametie. 
