98 
VEAL TO REE, 
[JUNE 1, 1899 
self in opposition to Darwin, Wallace, Fritz Muller, 
Weismann, and most of those whose labours have con- 
tributed to the establishment of the theory of evolution. 
But in speaking of views which he does not himself hold, 
he repeatedly allows himself to use language which is 
highly unbecoming in a scientific man. This is especially 
noticeable in his remarks on the subject of mimicry. 
We are of course prepared to find that he does not be- 
lieve in it, but it might be thought that a view which 
commended itself to Bates, Wallace, F. Miller, and. 
Trimen, to say nothing of Darwin himself, was at least 
deserving of respectful treatment. M. Piepers does not 
think so, and his language on the subject is so uncon- 
trolled as to suggest doubts whether, in spite of his 
training as a jurist, he can be considered a fair and com- 
petent examiner of evidence. It is easy enough to throw 
about words like “ Aberglaube” and ‘“ Humbuglehre” in 
reference to the views of other workers, and to suggest 
that opponents are “mentally abnormal” ; but such ex- 
pressions recall the methods of the advocate rather than 
of the judge, and they render their employer liable to 
severe retaliation, did any one care to administer it. 
A conspicuous instance of this want of restraint occurs 
in the note on p. 279; where the author altogether over- 
reaches himself in his denunciation of Schréder. It is 
not our business to correct his literary blunders, but we 
cannot help thinking that the original utterer of the 
famous line “homosum; humani nil ame alienum puto” 
(misquoted, by the way) would be somewhat surprised to 
see himself referred to as “ the old philosopher.’ This, 
however, may pass ; more open to question is the wisdom 
of introducing the quotation at all. M. Piepers seems to 
think that the upholders of mimicry will be “angry” at 
his strictures. They are more likely to be amused, and 
perhaps a little saddened, for there is always an element 
of pathos in resistance to the inevitable. 
Protective resemblance, in relation to selection, fares 
no better with the author than mimicry itself. Thayer’s 
demonstration of the protective value of the pale under- 
side of birds and mammals is convincing enough for 
most minds ; Piepers simply dismisses it with the remark 
that he cannot admit it in the case of insects. One is 
tempted to ask him what he expected in the case of 
insects, but this dictum is a not unfair specimen of his 
critical method generally. It is difficult to answer a dis- 
putant who holds (p. 250) that the resemblance to forms 
of vegetation shown by the underside of Euchloe carda- 
mines and even of Kadllima paralecta is accidental. The 
somewhat unseemly comparison on the same page is 
perhaps meant for a joke. If so, it says very little for 
the author’s humour ; if not, it says even less for his logic. 
The treatment of seasonal forms affords another 
instance of his curious reluctance to accept the plain 
and obvious explanation of certain facts, if that explan- 
ation involves a recognition of the principle of selection. 
Some of his remarks on the varying forms of Malayan 
butterflies have all the interest and importance which 
naturally belong to the personal observations of a good 
field naturalist, but it is strange to find him still ad- 
vancing theories of the direct influence of local conditions 
which were long ago discarded by Wallace. The truth 
which underlies his statements is probably this—that 
polymorphism gives an opportunity to selection, under 
NO. 1544, VOL. 60] 
which influence it may become limited by locality and 
season. In his discussion of the permanent or variable 
whiteness of certain animals, he cannot of course shut his 
eyes to the fact that the same visual effect of whiteness is 
produced in different cases by different means. He 
remarks in a somewhat puzzled way that there is never- 
theless evidently some connection between the whiteness 
caused by a white pigment (so-called) and that due to 
scattered reflection. Of course there is, or may be, such 
a connection ; but the obvious key to the mystery, viz. 
selective adaptation, is not even noticed by him. 
It 1s really pitiful to witness the straits to which those 
evolutionists are reduced who desert the firm and clear 
lines laid down by Darwin. Towards the end of his 
treatise M. Piepers makes a certain appeal for the in- 
dulgence due to an amateur. We are inclined to admit 
his claim, and to judge him leniently on that account. 
Courage and candour he does not lack, and it is deplor- 
able that having tasted the “ Pierian spring,” he has not 
taken a deeper draught of its waters. A little more 
reading would have shown him that many of his dis- 
coveries had been already made, and that most of his 
difficulties had been answered by anticipation. 
1a) Ne 1D): 
PROFESSOR TAIT’S COLLECTED PAPERS. 
Scientific Papers. By Peter Guthrie Tait, M.A, 
Sec.R.S.E., &c. Vol. i. Pp. xiv + 498. (Cambridge 
University Press, 1898.) 
HE Cambridge Press has already laid mathematical 
and physical workers under deep obligations by its 
editions of Maxwell, Stokes, Thomson, and Cayley. It 
now proposes considerably to extend these obligations, 
and as an instalment of their fresh enterprises we have 
here the first volume of the collected papers of Prof. Tait. 
This reprint appeals to readers of widely different 
interests, and will be welcomed by all, not only on account 
of the highly specialised investigations of various kinds 
which it contains, but also as a monument to a writer to 
whom science owes a great deal. ‘ 
It would be out of place, even if the reviewer were com- 
petent, to attempt any detailed examination of the papers 
here presented. They have been before the world for 
many years, and their value and originality have not been 
contested. A rapid sketch of the contents may, however, 
be given. A large proportion of the book is taken up 
with the quaternion investigations in which Prof. Tait 
first made his mark, and to which he has returned from 
time to time with undiminished enthusiasm. The precise 
scope and value of the quaternion method are questions 
on which opinions have greatly differed, and the number 
of mathematicians otherwise eminent who could be 
reckoned as fully concurring in Prof. Tait’s views on 
these points is probably very limited. In this country 
there has been a certain natural diffidence, and perhaps 
a little want of courage, which have hindered the free ex- 
pression of opinion ; but on the continent the assertion 
has been made again and again that the subject has in 
some respects been unfortunate in its expositors, and 
that the elements of undoubted value in the theory have 
been unduly discredited by the somewhat excessive 
claims made on its behalf. It is possible to sympathise 
