KARYOKINESIS AND ITS RELATION TO FERTILIZATION. 255 
plasma of the mother of the first generation be a, and that of the 
father a,, then the Keimplasma of the offspring has a composi- 
tion a+a,; therefore we must say, with regard to the amount 
of the latter, that it has a formula c+o= since, 
otherwise, the cells in the offspring would contain double as 
much Keimplasm as those in their parents. In the same way 
we must, if we would calculate the relative quantity, give to 
the keimplasm of the third generation the formula a 
And so there must occur in each generation a further halving 
of the received “ Ahnenplasma” (ancestral plasma), as Weis- 
mann calls the Keimplasm inherited from predecessors ; that 
is, the masses of every one of the different Ahnenplasmas must 
diminish in geometrical progression. If we take again the 
Biblical age of mankind as a basis (5000 years), and for every 
100 years reckon three generations, the amount of any one 
Ahnenplasma, say a, which would be present in the existing 
generation, would be expressed by the formula 7 : an amount 
the smallness of which is inconceivable. If we also suppose 
the Ahnenplasma to consist of “ units ” or granules so small as 
to be no longer divisible without losing their character as an 
hereditary substance, we shall arrive very soon at the limit of 
division ; in other words, the reproductive cells of any existing 
animal or plant contain already as many different Ahnen- 
plasmas as they can take up. How then can a reproduction 
with heredity take place to-day, when, since we cannot reduce 
the unit further, the mass of Keimplasma in each fertilization 
must be doubled ; which is not tenable, since each nucleus can 
only contain a certain amount of Keimplasma? 
The remedy for this is, according to Weismann’s hypothesis, 
afforded by the extrusion of the second directive corpuscle. 
Just so much “ Ahnenplasma”’ as arrives through fertilization 
will thereby be eliminated each time, and herewith the neces- 
sary corrective will be applied. But at the same time some- 
thing else is attained and explained herewith. The “ Ahnen- 
