At the close of my article in last month's number of the _Universal
Review_, I said I would in this month's issue show why the opponents of
Charles-Darwinism believe the effects of habits acquired during the
lifetime of a parent to produce an effect on their subsequent offspring,
in spite of the fact that we can rarely find the effect in any one
generation, or even in several, sufficiently marked to arrest our
attention.
I will now show that offspring can be, and not very infrequently is,
affected by occurrences that have produced a deep impression on the
parent organism--the effect produced on the offspring being such as
leaves no doubt that it is to be connected with the impression produced
on the parent. Having thus established the general proposition, I will
proceed to the more particular one--that habits, involving use and disuse
of special organs, with the modifications of structure thereby
engendered, produce also an effect upon offspring, which, though seldom
perceptible as regards structure in a single, or even in several
generations, is nevertheless capable of being accumulated in successive
generations till it amounts to specific and generic difference. I have
found the first point as much as I can treat within the limits of this
present article, and will avail myself of the hospitality of the
_Universal Review_ next month to deal with the second.
The proposition which I have to defend is one which no one till recently
would have questioned, and even now, those who look most askance at it do
not venture to dispute it unreservedly; they every now and then admit it
as conceivable, and even in some cases probable; nevertheless they seek
to minimise it, and to make out that there is little or no connection
between the great mass of the cells of which the body is composed, and
those cells that are alone capable of reproducing the entire organism.
The tendency is to assign to these last a life of their own, apart from,
and unconnected with that of the other cells of the body, and to cheapen
all evidence that tends to prove any response on their part to the past
history of the individual, and hence ultimately of the race.
Professor Weismann is the foremost exponent of those who take this line.
He has naturally been welcomed by English Charles-Darwinians; for if his
view can be sustained, then it can be contended that use and disuse
produce no transmissible effect, and the ground is cut from under
Lamarck's feet; if, on the other hand, his view is unfounded, the
Lamarckian reaction, already strong, will gain still further strength.
The issue, therefore, is important, and is being fiercely contested by
those who have invested their all of reputation for discernment in
Charles-Darwinian securities.
Professor Weismann's theory is, that at every new birth a part of the
substance which proceeds from parents and which goes to form the new
embryo is not used up in forming the new animal, but remains apart to
generate the germ-cells--or perhaps I should say "germ-plasm"--which the
new animal itself will in due course issue.
Contrasting the generally received view with his own, Professor Weismann
says that according to the first of these "the organism produces germ-
cells afresh again and again, and that it produces them entirely from its
own substance." While by the second "the germ-cells are no longer looked
upon as the product of the parent's body, at least as far as their
essential part--the specific germ-plasm--is concerned; they are rather
considered as something which is to be placed in contrast with the _tout
ensemble_ of the cells which make up the parent's body, and the
germ-cells of succeeding generations stand in a similar relation to one
another as a series of generations of unicellular organisms arising by a
continued process of cell-division." {30}