The Chromosomes of Eiischistus variolarius, Euschistus servus etc. 
491 
revived tlie hypothesis that the chromosomes are the bearers and distri- 
buters of all hereditary characters. In our preliminary note we stated 
the case as follows: 
“Behef in such a fundamental significance of the chromosomes has 
led its firmest adherents to Interpret every phase of their morphological 
and physiological expressions into terms of a causal nature, even to the 
point of claiming that definite chromosomes — such as the so-called sex- 
chromosomes — are the determining factors of sex and of all sex-linked 
characters. 
On the other hand a large number of cytologists have Studie d the 
clu’omosomes from an entirely different point of view — Iteheving that 
their morphological phases are not to be interpreted in terms of a causal 
nature, but like many other organs of the cell they are the expression 
rather than the cause of cell activities. 
These opposing interpretations can be strikingly demonstrated l)y a few 
quotations from recent papers. Morgan (’ 11) writes: “The experiments 
on Drosophila have led me to two principal conclusions : First, that sex- 
limited inheritance is explicable on the assumption that one of the material 
factors of a sex-limited character is carried by the same chromosomes that 
carry the material factor for femaleness. 
Second, that the ‘association’ of certain characters in inheritance 
is due to the proximity in the chromosomes of the Chemical substances 
(factors) that are essential for the production of those characters” 
(pag. 365). 
Wilson (’12) gives the stamp of his approval to Morgan’s conclusions. 
He says Morgan’s results “bring strong support to the view that the chro- 
mosomes are such bearers of unit-factors, for the whole series of pheno- 
mena determined in Drosophila, complicated as they seem, become at 
once intelligible under the assumption that certain factors necessary 
for the production of the sex-limited characters are borne by the X chro- 
mosome; and without this assumption they are wholly mysterious” 
(pag. 420-421). 
As opposed to these definite expressions of faith in the causal nature 
of the chromosomes, we may quote Child’s latest repudiation of all such 
hypotheses. “Lct us take the case of the chromosome, for example, 
which plays so important a part in recent biological hypothesis. WTiat 
is the chromosome? If it is what many authors seem to believe, it 
is an autonomous being endowed with something more than human 
intelligence. But if we are not willing to believe this, then we must 
regard the chromosome as an incidcnt or result of dynamic processes 
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