66 MARCUS M. HARTOG. 
Parallel cases of failure by continued association are nume- 
rous, both in organic life and in human affairs. Seed raised on 
the same soil for several generations yields stronger plants 
when transferred to a different soil or another climate. In a 
great business the disadvantages of too unchanged a manage- 
ment or a staff are recognised. 
As cell multiplication is essentially an exhaustive process, 
requiring nutrition to compensate for the losses incurred by 
the active metabolism involved, it is obvious that any accel- 
eration of the rapidity of the fissions and reduction of the 
interval of recovery of the cell must necessarily weaken the 
organism in a sort of multiple ratio, and so precipitate 
degeneration. 
In this way we can see how the reproductive incapacity of 
obligatory gametes may be frequently effected merely by the 
rapidly succeeding fissions that differentiate them. The re- 
placement theory of Balfour is true in its main proposition, 
that the formation of polar bodies is a process whose object 
is to prevent parthenogenesis ; though not by the mechanism 
he implies, the removal of a male element. The rapid celi 
divisions, uninterrupted by any interval for nuclear rest and 
reconstitution, must precipitate and accentuate reproductive 
incapacity—a view which is essentially O. Hertwig’s.' It is 
probably due to this physiological gain to the race that the 
page of morphological history, revealing that the oogamete 
was primitively one of a brood of at least four, has not been 
obliterated from the ontogenetic records of the Metazoa. 
From the standpoint that a well-constituted cell should be 
capable of doing anything that any cell can do—feeding, 
moving, growing, dividing, and so on—our specialised gametes 
are indeed stricken with utter degeneration; for they can 
neither feed, move (as far as the oogamete is concerned), 
grow, nor reproduce their kind, but as individuals are doomed 
to death or to the extinction of their individuality in a zygote. 
1 But it does not seem made out or even probable that in gametogeny the 
nuclear divisions proceed, as a rule, in the same breathless hurry as in Ascaris 
megalocephala; they certainly do not in the Angiospermous embryo-sac, 
