304 



NATURE 



[Feb. 17, 1876 



suffering hosts was expressly designed in order that man 

 might appreciate the benevolence of the " Creator." 

 Such a conception is too horrible to be entertained by 

 reasonable creatures ; nevertheless, it is in perfect har- 

 mony with certain other grossly anthropomorphic con- 

 ceptions of Deity that are too commonly, taught 

 amongst us. 



The general reader will not be able to follow M. Van 

 Beneden very closely, unless he possesses a considerable 

 amount of zoological knowledge ; and he will find the book 

 overladen with scientific terms. The naturalist, on the 

 other hand, will be disappointed by the paucity of lite- 

 rary references. Whilst our author shows himself to 

 possess a profound knowledge of the facts of commen- 

 salism, his volume is very deficient in the treatment of the 

 subject of parasitism, properly so called, more especially 

 when he deals with those forms that are known as Entozoa. 

 He has omitted all mention of some of the most important 

 helminthological contributions and discoveries of recent 

 times. Thus, there is no allusion to Lewis's " find " re- 

 specting nematoid hasmatozoa, and almost nothing is 

 said of the ravages produced amongst domesticated ani- 

 mals by a variety of well-known internal parasites. In 

 some places our author misleads, as in the case of the 

 history of the discovery of Trichina, where Sir J, Paget's 

 name is altogether omitted ; and also, in the case of 

 Bothriocephaltis, where Knoch's views on the possibility 

 of infection without the necessity of an intermediary 

 bearer appear to be countenanced. 



Some of the illustrations are very poor, and the mis- 

 spelling of authors' names and of technical words is 

 exceedingly frequent. The author appears to be but little 

 informed respecting the writings of German and English 

 helminthologists. Notwithstanding these defects, M. 

 Van Beneden's book ought to be purchased by every 

 intelligent naturalist. T. S. Cobbold 



OUR BOOK SHELF 



The Scholar's Algebra : an Introductory Work on Al- 

 gebra. By Lewis Hensley, M.A. (Oxford : Clarendon 

 Press ; London : Macmillan and Co., 1875.) 



This is one of the Clarendon Press Series, hence we are 

 saved all necessity of remarking upon the get-up of the 

 volume. We had hardly expected that Mr. Hensley 

 could have imparted any freshness to his treatment 

 of so hackneyed a subject as an Elementary Algebra, 

 but he has done so, and we have read his work with 

 much interest. It does not follow the usual course ob- 

 served in similar treatises either in its contents or in 

 their arrangement. Our author himself expressly states 

 that the work professes to be an introductory one on 

 algebra. He takes up the scholar who has been well- 

 grounded in arithmetic and endeavours to explain from 

 the outset what algebra is, what its aims, and what the 

 chief forms of its utility. In this attempt he has suc- 

 ceeded, and tlie work is likely to be of use to students 

 who are reviving an acquaintance with the subject 

 acquired at school, but especially is it suited to self-taught 

 students. For these latter it is, we think, one of the best 

 text-books hitherto brought out. The first seventy pages 

 are devoted to the symbols, signs, and elementary rules ; 

 in this section we have a good chapter on Ratio and Pro- 

 portion, including a glance at incommensurables. Though 

 treated at this length, the scholar is hardly likely to grow 

 weary in his work, and he is laying at the same time a 

 safe and solid foundation for future use. I tinction. 



In Part II. we have Algebraical formulae (Interest, the 

 Progressions), then Equations (Simple and Quadratic), 

 next Investigation of Methods (Involution and Evolution), 

 closing with a supplement on unknown quantities, In- 

 equalities, Indices (fractional and negative). The third 

 Part opens up to the student under Algebraical formulas. 

 Permutations, Binomial Theorem, Notation, Harmonic 

 Progression, and simple series, then Equations (more 

 advanced than the previous ones), Surds, Indeter- 

 minate Equations and applications of Horner's method. 

 We have then a chapter on Continued Fractions ^ 

 and another on Logarithms. Some idea of the 

 character of the work will be got from the order 

 and nature of the subjects above mentioned, and it 

 will be seen that a prominent feature is the import- 

 ance attached to methods of calculation. Indeed, Mr. 

 Hensley says he has remarked in the Universities a 

 growing disposition to compel the student of the higher 

 mathematics to interpret his results numerically. To this 

 he gives the weight of his experience : " There can be no 

 better guarantee that he understands what he is about." 

 We may mention that the extension of meaning of the 

 negative sign and of symbols generally, though but 

 slightly glanced at, is yet introduced to the reader's 

 notice. No place is given to properties of numbers, mul- 

 tinomial theorems, convergency of series, higher series, 

 or probabilities. The curriculum is much that laid 

 down by the London University for candidates for the 

 first B.A. (Pass), and we can recommend the book before 

 us as one well suited for such candidates, as containing 

 all they require, and but little beyond what they need take 

 up for the examination. 



We shall touch lightly here upon the errata. They are 

 not very serious, and though somewhat numerous, do not 

 by any means come up to the usual standard in this 

 respect of first editions. On p. 98, line 5, for youngest 

 read eldest ; p. 127, last three lines, statements should be 

 vice versd ; p. 205, line 5 up, read 7 X 52. 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the -writers of, rejected manuscripts. 

 No notice is taken of anonymous communications.'^ 



Fritz MuUer on Brazil Kitchen Middens, Habits of 

 Ants, &c. 



[.Mr. Charlks Darwin has kindly sent us for publication the 

 following letter, addressed to him by Herr Fritz Muller, the 

 well-known naturalist, brother of our contributor, Dr. Hermann 

 Muller, and who has for so long been devoting himself to natural 

 history researches in Brazil.] 



My dear Sir, — In Desterro I met with two young men (M. 

 Charles Wiener, of Paris, and M. Carl Schreiner, from the National 

 Museum of Rio) who, by order of the Brazilian Government 

 were examining the " Sambaquis " of our province. I accom- 

 panied them in some of their excursions. These " Sambaquis," 

 or " Casqueiros," are hillocks of shells accumulated by the 

 former inhabitants of our coast ; they exist in great number, and 

 some of them are now to be found at a distance of several miles 

 from the sea-shore, though originally they were, of course, built 

 near the spot where the shells lived. Some are of considerable 

 size ; we were told that a Sambaqui on a little island near SaO 

 Francisco had a height of about 100 metres ; but the largest I 

 have seen myself did not exceed 10 or 12 metres. As to the 

 shells of which they are composed, the Sambaquis may be 

 divided into three classes, viz. : (i) Sambaquis, consisting of many 

 different species of bivalve and univalve shells (Venus, Caidium, 



I We observe that our author says that these were first used by Lord 

 Brounker ; it has been shown that Cataldi has a pnor claim to this dis- 



; 



