May 12, 1910] 



NATURE 



309 



mar all mere compilations, however conscientiously 

 they may have been done. 



Although there are a good many errors, both of 

 commission and omission, in this book, and many 

 statements which we cannot endorse, the work is, 

 on the whole, the best elementary text-book on the 

 anatomy of the human nervous system, and it cer- 

 tainly contains the most useful account of the develop- 

 ment of the human brain that has appeared in a 

 student's text-book. If it were not for the difficulty 

 of language the book would appeal to a large class 

 of students and medical men. G. E. S. 



OVR BOOK SHELF. 



Tile Miners' Guide. By F. P. Mennell. Pp. viii + 196. 



(London : Gerrards, Ltd., 1909.) Price 45. net. 

 This little book aims at being a guide to the prospector, 

 and should largely attain its object. It is neither 

 lengthy nor profound, but sketches, lightly, those prin- 

 ciples of geology it is desirable that the prospector 

 should be acquainted with. 



In discussing the source of metals in lodes the 

 author appears to lean strongly to the theory of 

 lateral secretion, and is at some pains to show how 

 large a quantity of metal may be contained in the 

 rocks of a mineral district, even when barely percept- 

 ible traces of its existence can be detected by analysis. 

 He is a firm believer in the underground circulation of 

 meteoric waters as a means of dissolving and concen- 

 trating these metals in lodes and other deposits, and 

 seems to doubt the existence of a bary-sphere. 



The description, in chapter iii., of the characters of 

 re bodies is all too short, and chapter iv., which is 

 Uevoted to prospecting, might also be expanded with 

 advantage ; but this is supplemented later by a review 

 of the occurrence of, and prospecting for, gold, silver, 

 platinum, the base metals, and other useful minerals 

 and precious stones. An important feature of this 

 portion of the book is a general account of the uses 

 of the different minerals, and the conditions necessary 

 to be observed in preparing them for the market. 

 Prices and production also receive some attention, and 

 the more important localities are cited. Chapter xi. 

 deals with sampling, and in the space available gives 

 a good description of the operations that must be 

 undertaken, and the rriethods of computation that 

 must be adopted, to ascertain the average value of a 

 lode sampled. The following statement, however, 

 ■■.As a guide to the possibilities of undeveloped 

 ground, geological knowledge is often worth any 

 amount of sampling, but the miner can only judge 

 from his own experience what scientific knowledge 

 enables the geologist to gauge by the help of theories 

 founded on other people's experience as well as his 

 own," seems to assume a dangerous position and to 

 tend to a reliance on theory, rather than actual test- 

 ing, to determine the value of any mineral deposit. 



The working notes are necessarily fragmentary, 

 dealing as they do with alluvial working, including 

 dredging; lode mining; methods of crushing, cyanid- 

 ing, &c. , in one short chapter. The book, however, 

 contains many useful hints, and is one that should 

 certainly appeal to the prospector in far lands. 



The Coccidae of Ceylon. By E. Ernest Green. Part 

 iv., with 39 plates. Pp. 251 + 344; plates xciv.- 

 cxxxii. (London : Dulau and Co., 1909.) 

 The work before us well illustrates the enormous 

 recent development of our knowledge of entomology, 

 for when Mr. Kirby published his " Catalogue of the 

 Described Hemiptera Heteroptera and Homoptera of 

 Ceylon," in the Journal of the Linnean Society 



NO. 21 15, VOL. 83] 



(Zoology, vol. xxiv., 1891), he was only able to 

 enumerate seven species of Coccidae from the island — 

 Lecittiium mangijerae. Green (1889); L. coffeae. 

 Walk. (1852); L. viride, Green (1889); L. nigrum, 

 Nietn. (1861); Pseiidococctis adonidum, Linn. (1758); 

 Coccus{'f) Horiger, Walk. (1858), and C. laniger. Kirb. 

 (1891). 



Shortly afterwards, however, Mr. Green took up 

 the systematic study of the Coccidae in earnest, with 

 such good results that he soon accumulated materials 

 for a monograph of the Coccidae of Ceylon. At fiirst he 

 estimated that it would probably run to four parts, 

 containing thirty plates each ; but now he finds that 

 " the present (fourth) part contains many additional 

 plates, which (with the several supplementary plates) 

 bring the total number up to 135, or fifteen more than 

 the number promised to my subscribers. For the 

 completion of the monograph it will be necessary to 

 bring out a fifth part, of double size, containing from 

 fifty to sixty plates." Even so, considering the rapidity 

 with which material accumulates, we should not be 

 surprised if a further extension, or a speedy supple- 

 mentary part, may not be found necessary. 



But, however this may be, part iv. contains the 

 conclusion of the subfamily Lecaniinae, with nine 

 genera and nineteen species; and the new sub- 

 family Asterolecaniinae, with six genera, 24 species, 

 and two varieties. 



The work is based almost entirely on Mr. Green's 

 personal observations, and a large proportion of the 

 species described and figured are new. We have noth- 

 ing but praise for the text and letterpress of this mono- 

 graph of a family of insects which is important both as 

 destructive to vegetation and, in some instances (as 

 in the cochineal insect), as yielding products of con- 

 siderable commercial value. 



Colonsay, one of the Hebrides. Its Plants : their Local 

 Names and Uses. Legends, Rtiins, and Place- 

 names. Gaelic Names of Birds, Fishes, <S-c. 

 Climate, Geological Formation, 6-c. By Murdoch 

 McNeill. Pp. viii + 216. (Edinburgh: David 

 Douglas, 1910.) Price 2s. 6d. net. 

 The main purpose of the author is to publish a list 

 of plants collected during some years' stay on the 

 island, to which he has added general notes on the 

 history, geology, and fauna. The author has been a 

 keen observer of the birds, both migratory and native ; 

 among the former are the barnacle goose, pintail 

 duck, and wild swan, while eider-duck and cormorants 

 live on the outlying reefs or unfrequented coast, and 

 guillemots, buzzards, and kestrel nest on the northern 

 shores. In the same localities with the eider-duck 

 are found shoals of seal, both the large grey and 

 common species. 



A chapter is devoted to the description of the woods, 

 lochs, and pastures. The lochs are the most inter- 

 esting botanically. The white water-lily, the common 

 reed, and bottle sedge are the most conspicuous plants 

 in the shallows; species of Potarnogeton and 

 Callitriche aiitumnalis are abundant in the deeper 

 waters. The enumeration of flowering plants and 

 ferns amounts to 567 species, but this number includes 

 garden escapes. The author has been fortunate in 

 obtaining the cooperation of special authorities on 

 certain genera. Mr. A. Bennet has identified a dozen 

 species of Potamogeton, and a similar number of 

 Rubi are given on the authority of Rev. W. M. 

 Rogers. Among the more typical and rare plants are 

 Spergularia rupestris. Lobelia Dortmanni, Sedum 

 roseiim, Myosotis repens and Ligttsticum scoticnm. 



The book is pleasantly written, and contains a 

 considerable amount of observational matter scattered 

 through its pages. The Gaelic names and quotations 

 will only be appreciated by a limited number of readers. 



