224 MARY T. HARMAN 
sion is, it must be such that at least those cells which give rise to 
the new germ cells will contain the bearers of the characteristics 
of the species, or the characteristics themselves in potentia. 
Strasburger, Weismann, Kolliker, and Oscar Hertwig, inde- 
pendently and almost at the same time, identified the nucleus 
as the bearer of the hereditary qualities. This view, while 
held by many, is by no means universally accepted. If it be 
true that the nucleus is the bearer of the hereditary qualities, 
and if division be amitotic, it must be assumed that the nucleus 
as a whole is the bearer of the characteristics, and, so far as the 
hereditary qualities are concerned, there can be no differentiation 
of the nuclear material. 
The theory of the continuity of chromosomes is far from being 
absolutely proved or universally accepted. However, Rabl, Zur 
Strassen, Boveri, Van Beneden, Morgan, Wilson, Payne and 
others have made observations that give some very strong evi- 
dence in favor of it. If it should be proved that amitosis does 
not take place in cells which are the progenitors of new individ- 
uals, this would give no direct proof of the theory. On the other 
hand, if it should be proved that amitosis does occur in cells that 
are the progenitors of new individuals, it would offer very strong 
evidence against it. If the nucleus divide amitotically, the chro- 
matin which goes to one daughter nucleus gets into that particu- 
lar daughter nucleus rather than into the other, by chance. 
Such a condition would be one of the strongest evidences against 
the continuity of chromosomes. 
If there be a mass division of the chromatin, and consequently 
no continuity of chromosomes, the accessory chromosome and 
the idiochromosomes and their relation to the determination of 
sex have no significance unless as Wilson (’06) and Morgan (’09) 
have suggested, sex is determined by the quantity of the chro- 
matin. Their regular occurrence and their uniform behavior in 
a species would be difficult to harmonize with amitotic nuclear 
division. 
