the more correct expression, merely for the sake of brevity. It is a matter
of course that a whole extremity, such as we have here chosen, cannot be
represented in the germ by a single determinant only, but requires a large
group of determinants.
[17] That this is not so in all cases has recently been shown by Dixey from
observations on certain white butterflies of South America which mimic the
Heliconids and in which a small, yellowish red streak on the under surface
of the hind wing has served as the point of departure and groundwork of the
development of a protective resemblance to quite differently colored
Heliconids. "On the Relation of Mimetic Characters to the Original Form,"
in the _Report of the British Association for 1894_.
[18] Oscar Hertwig, _Zeit-und Streitfragen der Biologie_, Jena, 1894. It is
customary now to look upon the preformation-theory of Bonnet as a discarded
monstrosity, and on the epigenesis of K. F. Wolff as the only legitimate
view, and to draw a parallel between these two and what might be called
to-day "evolution" [i. e. unfoldment] and epigenesis. The evolution, or
unfoldment, of Bonnet and Harvey, however, was something totally different
from modern doctrines of evolution, and Whitman is quite right when he says
that even my theory of determinants would have appeared to the inquirers of
the last century as "extravagant epigenesis." Biologists in that day were
concerned with quite different questions from what they are at present, and
although now we probably all share the conviction of Wolff that new
characters do arise in the course of evolution, yet the acceptance of this
view is far from settling the question _as to how these new characters are
established in the germ-substance_--for in this substance they certainly
must have their foundation. When, therefore, O. Hertwig laments over my
regarding evolution and not epigenesis as the correct foundation of the
theory of development, his sorrow is almost as naive as is the statement of
Bourne that epigenesis is a fact and not a theory "a statement of
morphological fact," _Science Progress_, April, 1894, page 108), or, as is
the latter's unconsciousness that facts originally receive their scientific
significance from thought, i. e. from their interpretation and combination,
and that thought is theory. And when S. Minot, as the leader of the
embryologists, carries his zeal to the pitch of issuing a general
pronunciamento against me as a corruptor of youth, in which he declares it
to be a "scientific duty to protest in the most positive manner against
Weismann's theory," I wonder greatly that he does not suggest the casting
of a general ballot in the matter. (See the _Biologisches Centralblatt_ of
August 1, 1895.) We see how with these gentlemen the wisdom of the
recitation-room regarding the infallibility of epigenesis has grown into a
dogma, and whoever ventures to disturb its foundations must be burnt as a
heretic.
[19] Oscar Hertwig, _Zeit- und Streitfragen der Biologie_, Jena, 1894.
[20] Nor will those, who demand a demonstration of "how the biophores and
determinants are constituted in every case, and must be arranged in the
architecture of the germ-plasm." (O. Hertwig, _loc. cit._, p. 137). As if
any living being could have the temerity even so much as to guess at the
actual ultimate phenomena in evolution and heredity! The whole question is
a matter of symbols only, just as it is in the matter of "forces," "atoms,"
"ether undulations," etc., the only difference being that in biology we
stumble much earlier upon the unknown than in physics.
[21] "Beitraege zur Kritik der Darwin'schen Lehre," _Biologisches
Centralblatt_, Vol. X., p. 449. 1890.
[22] Poulton has adverted to the fact that this is nevertheless not always
the case; for example, it is not so with the teeth, whose shape it had also
been sought to reduce to the mechanical effects of pressure and friction.
See "The Theory of Selection" in _The Proceedings of the Boston Society of
Natural History_, Vol. XX., page 389. 1894.
[23] As the highest stage of selective processes must be regarded that
between the highest biological units, the colonies or cormi--a stage,
however, which is not essentially different from personal selection. In
this stage the persons enact the part that the organs play in personal
selection. Like their prototypes they also battle with one another for food
and in this way maintain harmony in the colony. But the result of the
struggle endures only during the life of the individual colony and can be
transmitted through the germ-cells to the following generation as little as
can histological changes provoked by use in the individual person. Only
that which issues from the germ has duration.
[24] This statement has often been declared extravagant, and it is so if it
is taken in its strict literalness. On the other hand, it would also seem,
by a more liberal interpretation, as if there existed non-adaptive
characters, for example, rudimentary organs. Adaptiveness, however, is
never absolute but always conditioned, that is, is never greater than
outward and inward circumstances permit. Moreover, an organ can only
disappear gradually and slowly when it has become superfluous; yet this
does not prevent our recognising every stage of its degeneration as adapted
when compared with its precursor. Further, it does not militate against the
correctness of the above proposition that there are also characters whose
fitness consists in their being the necessary accompaniments of other
directly adapted features, as, for instance, the red color of the blood.
[25] Semper, _Die natuerlichen Existenzbedingungen der Thiere_, Leipsic,
1880, pp. 218-219.
[26] Wolff, "Beitraege zur Kritik der Darwin'schen Lehre," _Biolog.
Centralblatt_, Vol. X., Sept. 15, 1890, and "Bemerkungen zum Darwinismus
mit einem experimentellen Beitrag zur Physiologie der Entwicklung,"
_Biolog. Centralblatt_, Vol. XIV., Sept. 1, 1894.
[27] Henry B. Orr, _A Theory of Development and Heredity_, New York, 1893.
[28] Yves Delage, _La structure du protoplasma et les theories sur
l'heredite et les grands problemes de la biologie generale_, Paris, 1895.
[29] Henslow, _The Origin of Species Without the Aid of Natural Selection,
A Reply to Wallace_. 1894.
[30] If any one should deem these words too severe, let him read the
sarcastic passages in which Eimer has dispatched the late unfortunate Eric
Haase who had been presumptuous enough to oppose the Tuebingen Professor's
deliverances on certain points. Haase, as we all know, fell a victim to the
climate of the tropics, shortly after resigning the post of Director of the
natural science collections in Bangkok, in order to return to Germany and
to work out the fruits of his tropical sojourn. The unfortunate end of this
accomplished man who had rendered important services to science had no
effect in mollifying the resentment of Herr Eimer at the opposition which
his views had encountered; and in twenty printed pages he takes him to task
in the most personal and rancorous manner for this affront, remarking at
the close: "In the meantime Herr Haase has died. Nevertheless I owe it to
myself, in spite of this occurrence, to make public the foregoing facts, in
order," etc. Any one who is interested in knowing the motives of Herr
Eimer's excuse may find them in his book _Artbildung and Verwandtschaft bei
den Schmetterlingen_, Part II., p. 66.
[31] "Gedanken zur Descendenz- und Vererbungstheorie." _Biolog.
Centralblatt_, July 15, 1893.
[32] C. Lloyd Morgan, _Animal Life and Intelligence_, London, 1890-1891, p.
30-33.
[33] _Materials for the Study of Variation with Especial Regard to
Discontinuity in the Origin of Species_, London, 1895, p. 16.
[34] "Gedanken zur Descendenz- and Vererbungstheorie," _Biolog.
Centralblatt_, 1893, Vol. XIII., p. 397.