July 1, 1895.] 



KNOWLEDGE. 



159 



It will also be seen, from Dr. Marshall's paper, that the 

 inferences drawn from the facts which he relates are, that 

 those butterflies which are thus protected surriir, while 

 those that are unprotected perish, or, at least, ai-e liable to 

 destrnction : aud the question naturally susr.Erests itself— 

 Why do any butterflies remain unprotected '.' Why has 

 Nature, by means of her handmaid — natural selection — 

 not aflbrded them the same protection as the others '? 

 and further — If some have remained unprotected for 

 •'thousands of generations," as Mr. Darwin would say, 

 how have they escaped destruction so long ? how have they 

 come also to survive, if protection is necessary, as Dr. 

 Marshall seems to say. for the preservation of their life '? 



Another inference, I think, is plainly deducible from 

 what is said, especially under the head mimicry, viz., that 

 the edible butterflies, seeking protection by mimicking 

 the warning colours of their inedible neighbours, evince an 

 amount of intelligence and knowledge of the effects of 

 different colours which we are hardly prepared to expect 

 from such low organisms as butterflies and caterpillars. 

 True, Mr. Wallace refuses to allow that the mimicry is a 

 voluntary act on the part of the insects, but he constantly 

 speaks as if it were, and the words "mimicks"' and 

 " mimicry " necessarily imply, as every school-boy knows, 

 an active agent, as, indeed, so do the words "natural 

 selection," as the Duke of Argyll and others have clearly 

 shown . 



Is there any well-authenticated case in Nature to support 

 such a view '? I have heard or read of none — the 

 chameleon is not a case in point. 



Remark also that insects, w^hich use warning colours, 

 are so considerate as to protect, not themselves only, but 

 even their enemies from injury. 



Agaui, I ask, if certain insects have been able to protect 

 themselves in this way, why do not all their neighbours 

 follow their clever example ? When I say "protect them- 

 selves," I only use a phrase which Mr. Wallace himself 

 uses, for at page 190 he says " domesticated animals 

 are protected by man — wild animals have to protect 

 themjielres." 



Altogether, I am constrained to look upon the theory 

 involved in Dr. Marshall's article as an entire misunder- 

 standing of the interesting facts which he relates, and to 

 ask — what has all this to do with the Oriijin of Species '.' 



Droughty Ferry. Wm. Miller. 



Notices of Boofts. 



British Mammalia. By R. Lydekker, B.A., F.R.S. Pp. 

 339. Os. Carnirora. By the same author. Pp. 812. Gs. 

 ( W. H. Allen & Co., Limited.) These are two new volumes 

 in the " Naturalist's Library," edited by Dr. Bawdier Sharpe. 

 The former is practically a revised and enlarged edition of 

 Macgillivray's work published in " .Jardine's Naturalist's 

 Library." With Mr. Lvdekker's name on the title-page 

 of this book, it is hardly necessary to say that the con- 

 tents are brought right into line with the presrnt state of 

 knowledge of our mammils. The advances that have been 

 made during the past twenty years, especially in regard 

 to the geographical distribution of mammalia, are all given 

 due consideration. The number of terrestrial mammals 

 which are regarded as indigenous inhabitants of Great 

 Britain during the historic period is forty-one, but five or 

 sis of these are now extinct. The poverty of Britain in 

 species is shown by the fact that Germany possesses nearly 

 ninety species and Scandinavia sixty. Various theories 

 have been put forward in connectioa with this distribution. 



Whether the ancient British fauna was entirely swept 

 away during the glacial period, or whether part of it 

 survi^■ed in the South of England, and afterwards spread 

 northward, is still an open question. In the former case 

 it is necessary to believe that Britain was connected with 

 the Continent after the glacial period : in the latter, 

 no such connection need be considered. Mr. Lydekker 

 says, " Whether, however, the one theory or the other of 

 the re-population of England be adopted, we have to 

 remember that the present impoverished mammalian fauna 

 of Britain as compared with the Continent is due to the 

 direct or indirect action of the glacial period, the eft'ects of 

 which have been so far-reaching both on inanimate and 

 animate nature in the northern hemisphere. " A section 

 on the ancient mammals of Britain, which originally 

 appeared in the columns of Knowledge, is included in the 

 volume. There are thirty-two plates, none of which, 

 however, call for special remark. 



The volume dealing with the order Carnivora furnishes 

 interesting reading on the characteristics and habits of 

 ] those well-known animals comprehended under the title 

 of cats, and including lions, tigers, leopards, pumas, tiger- 

 cats, domestic cats, and lynxes. Besides the cats, the 

 volume deals with those near relations, the civets and 

 mangooses. The family Fdida, however, is naturally 

 treated in more detail, and a larger number of species are 

 illustrated, than in the family JAverrida. An account of 

 fossil species forms the concluding section of the work. 

 We think both volumes are very valuable additions to the 

 series in which they appear. 



The Moon. By T. Gwyn Elger, F.R.A.S. Pp. 173. 

 (George Philip & Son.) os. Mr. Gwyn Elger ranks 

 among the foremost selenographers, so this work of his 

 may be relied upon as a trustworthy guide to the physical 

 features of our satellite. All limar objects of interest and 

 importance are referred to, and, as might have been 

 expected from an observer who has devoted his attention 

 to lunar scenery for thirty years or so, their characteristics 

 are truthfully described. A short history of observations 

 of the moon, embodying a general account of the difl'erent 

 kinds of formations observable, and statements of the 

 speculations relating to lunar " geology," is contained in 

 an introduction. Tlien comes the practical part of the 

 book, and this is rendered exceedingly valuable by the fine 

 map of the moon reproduced in four sections, each quadrant 

 occupying a double page. This map is, without doubt, the 

 clearest and most complete representation of the moon's 

 surface available on the same scale, viz., eighteen inches 

 to the moon's diameter. Taking each quadrant in turn, 

 Mr. Elger describes all the interesting objects in them, 

 and also a few features which, on account of their minute- 

 ness, could not be shown with any advantage on the map. 

 Observers of the moon will find the volume meets all their 

 requirements. The work is handy for reference, and is 

 published at a reasonable price. It will doubtless become 

 an indispensable companion to the telescope. 



The Theory of Liffht. By Thomas Preston, M. A. Pp.566. 

 (Macmillaa & Co.) 153. net. This is a secand edition of a 

 work familiar to all physicists. The author aimed at pro- 

 ducing " an accurate and connected account of the most 

 important optical researches from the earliest times up to 

 the most recent dite," and tho^e who are competent to 

 judge know that he accompUshed his purpose. The text 

 of the new edition has been revised throughout, and more 

 than one hundred pages of new m^lter have been added, 

 as well as several new diagrams. These additions increase 

 the value of a volume that has been regarded as a standard 

 work on the theory of light ever sinie it first appeared. 



