458 



NATURE 



{Sept. 15, 1 88 1 



was just about to hop into it when it caught si;^ht of the 

 caterpillar, and btood jerking its head from side to side, 

 but did not venture to enter. Another bird sooa came, 

 and behaved in a precisely similar manner; then a th;rd. 

 and a fourth ; others settled on the perch over the trou^jh, 

 and a flock of ten or twelve were finally perjhed around. 

 They all stretched their heads and looked into the trough, 

 but none flew into it." 



On removing the caterpillar the birds again assembled, 

 and at once entered the trough to feed. Fowls were also 

 frightened at first, and would draw back just as they 

 were going to peck at the caterpillar. At last, after several 

 had tried, and even made ineffectual attempts to peck, 

 one more courageous than the rest would actually touch it, 

 and after a time, finding nothing disagreeable, the insect 

 would be swallowed. In the genus Deilephila, however, 

 there are unsalable caterpillars, and these have strongly 

 contrasted black and white or yellow- spots combined with 

 the habit of fully e.xposing themselves upon their food 

 plants. Dr. Weismann experimented with two species 

 {D. gain and D. cuphorbice) and found that they were 

 refused by birds, though the latter was eaten by lizards- 

 It is to be noted however that the experiments were made 

 with a South European specie's of lizard, not that of 

 Germany, so that the result has not a direct bearing on 

 the point. 



The general conclusion at which Dr. Weismann arrives 

 is, that all the varieties of colour and marking occurring 

 in the Sphingida: have a distinct biological value, and can 

 in every case be traced to the action of natural selection 

 and correlation of growth. 



The next essay is not quite so interesting or important. 

 It is an endeavour to prove, by a distinct line of inquiry, 

 that the markings of the larva; are not due to a "phyletic 

 vital force "or to general laws of growth and develop- 

 ment. The different groups of Sphingidas are minutely 

 examined and compared in their three stages of larva, 

 pupa, and imago, and it is shown that the changes that 

 occur from species to species in each stage are to a great 

 extent independent of the changes in the other stages. 

 Numerous examples of this want of phyletic parallelism 

 are given, and it is hence argued that the modifications 

 which occur must be due to an adaptation to the special 

 conditions to which the insect is exposed in one or other 

 of its states, not to any innate law of variation and deve- 

 lopment, which, it is argued, would affect all the stages 

 pari passu and produce a " phyletic parallelism" which 

 does not actually exist. The same general facts are 

 shown to prevail, not only among Lepidoptera generally, 

 but among all insects and Crustacea— or generally among 

 all organisms which undergo a metamorphosis. 



This instalment of the work has been admirably trans- 

 lated and edited by Mr. Meldola, who, in a series of 

 valuable notes and an Appendix, has brought up the 

 information on every branch of the inquiry to the latest 

 date. The six coloured plates of larva: in their several 

 stages are very well executed, and serve to illustrate the 

 somewhat complex discussion in a clear and effective 

 manner. Alfred R. Wallace 



OUR BOOK SHELF 

 The Wandering Jew. By Moncure Daniel Conway. 



(London : Chatto and Windus, 1881.) 

 This last volume of Mr. Conway's is a study, not only of 

 the legend of the Wandering Jew, but with it of the large 



group of analogous myths of undying men who from age 

 to age wander over the earth, or sleep in caverns, or are 

 transLted from among men into divine regions, whence 

 however they come back and show themselves still living 

 men. The interest of these stories in the history of 

 philosophy lies in their keeping up men's early ideas of 

 life and death. One of Mr. Conway's purposes in dis- 

 cussing them is to draw attention to their being relics of 

 the primitive period when men were still so far from 

 definitely realising the nature of death, that they had no 

 difficulty in regarding king^, heroes, and prophets as 

 having only departed for a while from among them, to 

 return in a future age to rule and protect their expectant 

 nations. In comparative mythology this group of stories 

 has so.ne importance. They show the beliefs of various 

 races running curiously into one another, as where the 

 Lancashire peasant still hears in the cry of the plover the 

 wail of the Wandering Jew, or in the Harz Mountains 

 his myth has got mixed with that of a grander wanderer, 

 the Wild Huntsman, who courses with his storm-clouds 

 across the sky. The storm-demon W'hom mythic fancy 

 imagines rushing through the air is often called a Mac- 

 cabee, and Mr. Conway points out why he has this name. 

 It is because of a verse in the Second Book of Macca- 

 bees, chap, v., which, by the way, is a good instance of the 

 personal forms taken by the fancy of an excited people : 

 " And then it happened, that through all the city, for the 

 space almost of forty days, there were seen horsemen 

 running in the air, in cloth of gold, and armed with lances, 

 like a band of soldiers.'' Unfortunately some other ety- 

 mologies made or quoted by Mr. Conway are not so 

 reasonable as this. When the names of biblical person- 

 ages, HeroJ and. Ahasiients, find their way into European 

 myths, it miy not be easy to explain how they got there, 

 but at any rate it is better to leave them alone than to 

 ma'-ce up imaginary and even impossible German or 

 Scandinavian forms, Haar- Role, As-Vidar, to account for 

 their presence. It would be easy to take e.xception to 

 many of the arguments in this volume, but at any rate 

 there are many interesting points in it. 



A Short Sketch of the Geology of Yorkshire. By Charles 

 Bird, B.A. (Univ.Lond.) (London : Simpkin, Marshall, 

 and Co. ; Bradford : Thomas Brear, 18S1 ; pp. 1S7 

 and Map.) 



Geological Map of Yorkshire. By the same Author. 

 (Edinburgh and London: W. and A. K. Johnston; 

 Bradford: T. Brear, iSSi.) 



In the preface of this boo';, written by way of dedication, 

 it is represented to be a " small and cheap volume suitable 

 to the 'general reader' and tourist.'' It is impossible to 

 say that it is not a useful and interesting one. So much 

 good work has been done on the county, though scattered 

 through very various publications, that a short resume 

 cannot fail to be of value ; but there are books and books, 

 and if we measure this by what it might have been, it is 

 poor indeed. It resembles, in fact, geologically speaking, 

 a kind of boulder clay, full of fragments of solid rock, 

 brought from a distance— we will not say to be deposited 

 in mud — but certainly scratched and rubbed in the pro- 

 cess. In the beginning of the volume is a list of the 

 surrounding mountains whence the boulders have been 

 derived, but it is not a complete one ; and the source of 

 each fragment is not indicated in the body of the text. 

 Its great defect is that it is unstratified; in other words, 

 the extracts are not duly digested, but thrown together with- 

 out sorting, and with very little alteration; so little indeed 

 that it would not be difficult to trace them to their sources. 

 Thus under the head of " The Carboniferous Period " we 

 have a brief explanation, from a popular lecture, "how 

 from the general mineral character of a rock the circum- 

 stances underwhioh it was formed can often be predicated." 

 Then under the head of "Suit water deposits" we have 

 twelve pages on the origin and contents of the Victoria 



