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                            AN EXAMINATION

                                  OF

                              WEISMANNISM




                                Oxford

                HORACE HART, PRINTER TO THE UNIVERSITY

[Illustration: AUGUST WEISMANN]




                            AN EXAMINATION
                                  OF
                              WEISMANNISM

                                  BY

                          GEORGE JOHN ROMANES
                          M.A., LL.D., F.R.S.
       HONORARY FELLOW OF GONVILLE AND CAIUS COLLEGE, CAMBRIDGE

                                London
                       LONGMANS, GREEN, AND CO.
                                 1893




PREFACE


AS already stated in the Preface to the second edition of _Darwin and
after Darwin_, Part I, severe and protracted illness has hitherto
prevented me from proceeding to the publication of Part II. It is
now more than a year since I had to suspend work of every kind, and
therefore, although at that time Part II was almost ready for press,
I have not yet been able to write its concluding chapters. Shortly
before and during this interval Professor Weismann has produced his
essays on _Amphimixis_ and _The Germ-plasm_. These works present
extensive additions to, and considerable modifications of, his previous
theories as collected together in the English translation, under
the title _Essays on Heredity, Vol. I_. Consequently, it has become
necessary for me either to re-write the examination of his system which
I had prepared for Part II of my own treatise, or else to leave that
examination as it stood, and to add a further chapter dealing with
those later developments of his system to which I have just alluded.
After due reflection I have decided upon the latter course, because
in this way we are most likely to obtain a clear view of the growth of
Weismann’s elaborate structure of theories—a view which it is almost
necessary, for the purposes of criticism, that we should obtain.

Having decided upon this point, it occurred to me that certain
advantages would be gained by removing the whole criticism from the
position which it was originally intended to occupy as a section of my
forthcoming volume on the Post-Darwinian period. For, in consequence
of the criticism having been written at successive intervals during
the last six or eight years as Professor Weismann’s works successively
appeared, it has now swelled to a bulk which would unduly encumber
the volume just mentioned. Again, the growth of Professor Weismann’s
system has of late become so rapid, that if the criticism is to keep
pace with it in future, the best plan will doubtless be the one which
it is now my intention to adopt—viz., to publish the criticism in a
separate form, and in comparatively small editions, so that further
chapters may be added with as much celerity as Professor Weismann
may hereafter produce his successive works. Lastly, where so much
elaborate speculation and so many changes of doctrine are concerned, it
is inevitable that some misunderstandings on the part of a critic are
likely to have arisen; and therefore, should Professor Weismann deem it
worth his while to correct any such failings on my part, the plan of
publication just alluded to will furnish me with the best opportunity
of dealing with whatever he may have to say.

It must be understood, however, that under the term “Weismannism” I
do not include any reference to the important question with which the
name of Weismann has been mainly associated—i.e., the inheritance or
non-inheritance of acquired characters. This is a question of fact,
which stands to be answered by the inductive methods of observation
and experiment: not by the deductive methods of general reasoning.
Of course Professor Weismann is fully entitled to assume a negative
answer as a basis whereon to construct his theory of the continuity of
germ-plasm; but no amount of speculation as to what the mechanism of
heredity is likely to be if once this assumption is granted, can even
so much as tend to prove that the assumption itself is true. Therefore,
in this “examination of Weismannism” I intend to restrict our attention
to the elaborate system of theories which Weismann has reared upon his
fundamental postulate of the non-inheritance of acquired characters,
reserving for my next volume our consideration of this postulate itself.

Lest, however, it should be felt that “an examination of Weismannism”
in which the question of the transmission of acquired characters is
omitted must indeed prove a case of Hamlet without the Prince of
Denmark, I may be allowed to make two observations. In the first
place, this great question of fact is clearly quite distinct from
that of any theories which may be framed upon either side of it.
And, in the second place, the question was not raised by Weismann. It
appears, indeed, from what he says, that he never caught a glimpse of
it till about ten years ago, and that he then did so as a result of
his own independent thought. Moreover, it is perfectly true that to
him belongs the great merit of having been the first to call general
attention to the subject, and so to arouse a world-wide interest with
reference to it. But to suppose that the question was first propounded
by Weismann is merely to display a want of acquaintance with the
course of Darwinian thought in this country. As far back as 1874 I had
long conversations with Darwin himself upon the matter, and under his
guidance performed what I suppose are the only systematic experiments
which have ever been undertaken with regard to it. These occupied
more than five years of almost exclusive devotion