58 EDWIN G. CONKLIN 
Actinosphaerium and Infusoria, which had been overfed for a 
long time, he found that there was an enormous growth of the 
nucleus followed by physiological degeneration. The animals 
which saved themselves from this condition did it by the reduction 
of their nuclei, either by eliminating nuclear substance directly, 
or by the loss of the greater part of the nuclear material during 
conjugation, after which normal nuclear conditions were restored. 
He regards the immature egg cell, with its great nucleus, as in a 
condition of depression similar to that found in the protozoa 
named. By the processes of maturation and fertilization this 
nuclear material is greatly reduced: ‘‘Beim Beginn der Fur- 
chung und auch spiter ein enormes Missverhdéltniss von Kern 
und Protoplasma vorhanden ist, und dieses Missverhaltniss 
allmiihlich eine Ausgleich erfaihrt, indem Zellsubstanz in Kern- 
substanz umgewandelt wird,” (’03, p. 116). Apparently then, 
in Hertwig’s view, senescence or depression, is accompanied by 
too great an amount of nuclear material, which is then reduced, 
by maturation in the case of the egg cell, to such an extent that 
this enormous disproportion of nucleus to protoplasm appears; 
later, by means of the process of cleavage, during which the 
nuclear material grows at the expense of the protoplasm, the 
normal relations of nucleus to protoplasm are restored. 
Popoff (08) accepts Hertwig’s view in all essential respects. 
He adds the interesting suggestion that in their period of depres- 
sion preceding maturation the sex cells are so weakened that they 
are unable to assimilate nutriment, and they consequently store 
up food as yolk. The formation of yolk, glycogen and fat are, 
according to this author, not indications of increased activity 
of cells, but of incapacity to carry the organic synthesis to its 
end, viz., the formation of plasma. 
While Minot’s hypothesis differs fundamentally from Hert- 
wig’s as to the cause of senescence, the former holding that it 
depends upon the increase of protoplasm over nucleus, the latter 
that it is accompanied by an increase of nucleus over protoplasm, 
both agree that in the segmentation of the egg there is an enor- 
mous growth of the nuclear material as compared with the pro- 
toplasm. 
