22 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
tion division. Brauer therefore contends that a Weismannian reduction 
is impossible in karyokinetic division, and indeed never oocurs. For 
Brauer the reduction question has consequently found its final solution : 
There is no reduction except merely one of mass. This would offer 
a very simple answer to the problem. But Henking (’90, "91, 792), 
Rückert (92, '03), Häcker (91, '93), and vom Rath (791^, '92, '93) have 
been able to see only one longitudinal splitting. I have seen no evidence 
of any such splitting of the chromatio thread in Caloptenus. Since com- 
ing to that conclusion, I have read in Born's paper on the egg of Triton 
(94) that he finds a doubling in the number of the chromatic elements 
during the germinative-vesicle condition, but this doubling does not 
result from a longitudinal splitting. The chromatic thread divides 
transversely into twice as many segments as there were chromosomes in 
the Ureizelle. Born’s statement that “eine Verdoppelung durch Quer- 
theilung stattfindet " is in essential agreement with my results, 
A remark by Wagner (92) — to the effect that twice as many 
chromosomes arise during the resting stage immediately before the first 
maturation division as were in the cells of the preceding generation, 
but that this does not imply any such definite longitudinal splitting 
as Brauer and other authors maintain — may also be interpreted as in 
harmony with my conclusions, 
Since the chromatin in the resting stage is very finely divided, — at 
least into finer particles than the “ Chromatinkörner " to which Brauer 
ascribes the dignity of individuality, — it seems to me just as arbitrary 
to consider these homogeneous “Chromatinkórner” units, which by di- 
vision must give rise to identical daughter grains, as to make the same 
supposition with regard to the chromosomes. 
But further, even if we grant for a moment that the Vierergruppen 
do arise by two longitudinal divisions of the chromatic granules, what 
evidence have we that each Vierergruppe consists of four identical 
elements? Brauer maintains that both these splittings take place very 
early in the resting stage. The granules are extremely small. Each 
chromatic quarter of the group increases considerably in size. This 
growth takes place while they are separated (held together only by 
linin threads). There is still the probability that chromatic substance 
is formed in the nucleus during the process, and becomes associated 
with the substance of the Vierergruppen. ln order to insure the 
identity of the elements of a Vierergruppe, two longitudinal divisions 
must take place after all growth of the chromatin has ceased, and we 
must at the same time assume that the chromatic elements are homo- 
