December 8, 19 lo] 



NATURE 



169 



Lastly, there comes a well-illustrated section on 

 milk products and the methods of working them up 

 for market. So important is cleanliness in working 

 that several pictures are given of modern cow-sheds 

 built on the best possible principles ; in one, indeed, 

 the cowman is shown cleansing the cow with a special 

 vacuum cleaner ! This section will probably prove 

 most interescinir to English readers, as it gives fairly 

 full outlines of the German factory methods. 



A few misprints are inevitable, but how did this 

 wonderful piece of Greek on p. 12 pass the proof- 

 reader *■ kohlenhydrate (von A-yfiop hydor = griechisch 

 wasser) "? E. J. R. 



fheorettcal Mechanics. By P. F. Smith and W. R. 



Longley. (Ginn.) Price 105. 6d. 

 L'ntil the student has acquired a certain manipula- 

 tive dexterity, it is impossible to preserve a proper 

 continuity of thought in the development of the appli- 

 cation of infinitesimal theory of mechanics or any 

 other applied science. The authors are therefore justi- 

 fied in assuming that the reader comes to this subject 

 equipped with a thorough working knowledge of the 

 methods of the calculus. In the opening chapter a 

 _;ood account is given of the means for obtaining 

 ■f-ntres of gravity and moments of inertia of plane 

 nd solid figures ; no mention is made, however, of 

 he application of orthogonal projection to the theory 

 f the centroid. Chapters ii.-iv. deal with the prin- 

 Jples of rectilinear and curvilinear motion in a most 

 attractive fashion ; as an example, the motion t\'pified 

 by .v = acosfef is considered, the equation d'x'dt^ = 

 — k^.x is deduced, and the properties of harmonic 

 motion are then obtained in a simple fashion ; a 

 similar treatment is applied to damped vibrations. 

 This is followed by an exposition of work, energv, 

 and impulse. Chapters vi.-ix. discuss the motion of 

 a particle under constant forces, central forces, in a 

 harmonic field, and against a resisting medium. The 

 volume closes with a brief account of the equations of 

 rigid dynamics and the principles of equiliSrium of a 

 coplanar system of forces with special reference to 

 the catenar^^ 



The examples, which are very numerous, are mainlv 

 numerical and practical, and so chosen as to require 

 ; minimum of analytical power. This feature renders 

 lie book eminently suitable for the senior divisions of 

 secondary schools, where the true understanding of 

 the ideas of mechanics is the chief object. It is to 

 be regretted that practically no English text-book has 

 treated the subject on these lines, a fact which is due 

 mainlv to the action of the universities in excluding 

 the simoler applications of particle and rigid dynamics 

 from their entrance scholarship examinations. We 

 hope that the time is not far distant when this re- 

 '-triction will be removed. 



The Anatomy of the Honey Bee. By R. E. Snod- 



grass. (U.S. Departrrtent of Agriculture, Bureau of 



Entomolog}-, Technical Series, No. 18.) Pp. 162. 



(Washington : 19 10.) 



In this modest pamphlet the author has given to 



t-ntomologists an original, trustworthy, and excellentiv 



illustrated account of the structure of the honev bee, 



and another instance has been furnished of the scien- 



fic thoroughness that characterises the publications 



if the United States Department of .Agriculture. 



Many volumes have been written on the honey bee, 



yet no surprise can be felt that Mr. Snodgras's has 



been able to add new points to our knowledge and 



to correct errors in the work of his predecessors. A 



feature of value to the serious student is the general 



-uryey of the external structure of a typical insect 



which the author has wisely given as an' introduction 



to his account of the highly specialised modifications 



NO. 2145, VOL. 85] 



to be found in the bee. He expresses scepticism as to 

 certain positive statements that have been made on 

 controverted details of physiology and reproduction ; 

 for example, " concerning the origin of the royal 

 jelly or of any of the larval food paste . . . we do 

 not know anything about it." There is a present-day 

 tendency unduly to disparage the results obtained by 

 former workers, and such a statement will strike 

 many readers as extreme. Mr. Snodgrass's sceptic- 

 ism as to the parthenogenetic nature of " drone " eggs 

 seems also unwarranted after the support which 

 Weismann's researches, published ten years ago, 

 afford to the generally accepted view. G. H. C. 



Practical Physiological Chemistry : a Book designed 

 for Use in Courses in Practical Physiological 

 Chernistry in Schools of Medicine and of Science. 

 By Philip B. Hawk. Third edition, revised and 

 enlarged. Pp. xviii + 440. (London : J. and A. 

 Churchill, 1910.) Price 165. net 

 Both the first and second editions of Prof. Hawk's 

 volume have been reviewed in these columns ; the 

 former in our issue of July 18, 1907 (vol. Ixxvi., p. 268), 

 and the latter in that of July 15, 1909 (vol. Ixxxi., 

 p. 67). The present edition has been brought up to 

 date by the insertion of various additions and correc- 

 tions, as well as by the inclusion of a number of 

 qualitative tests and quantitative methods. 



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 intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



Simulium Flies and Pellagra. 



In reference to Mr. Shelford's letter in Nature of 

 November 10, in which he directs attention to the difficul- 

 ties in controlling and eradicating the flies of the genus 

 Simulium, known generally as sand flies and black flies, 

 it may be of interest to direct attention to certain experi- 

 ments carried out in New Hampshire by Dr. C. M. Weed 

 and Prof. E. Dwight Sanderson and their assistants in 

 the control of these insects. The southern buffalo gnat, 

 Simulium pecuarum, Riley, which attacks and kills many 

 animals, such as horses, cattle, mules, sheep, poultr}', 

 dogs, &c., is well known. In certain parts of the United 

 States, but especially in Canada, " black flies," generally 

 S. hirtipes. Fries, and S. venustum, Say, make life far 

 more intolerable than mosquitoes, and they are specially 

 annoying when they occur in such resorts as the White 

 Mountains. 



In 1903 Dr. Weed and his assistant, Mr. A. F. Conradi, 

 showed that the Simulium larvae, although they live on 

 the stones in running water, could be killed by the appli- 

 cation of Phinotas oil. The destruction was so complete 

 that the flies were practically eradicated in the locality 

 in which the experiments were carried out (see " Experi- 

 ments in Destroying Black Flies," Bull. No. 112 New 

 Hampshire .Agric. Exp. Sta., 1904). A floating oil such 

 as kerosene is manifestly useless for the destruction of 

 larvae having such habits as Simulium, and the efficacy 

 of Phinotas oil is due to the fact that it has the property 

 of sinking to the bottom in water, thus destroying the 

 larva? which are stationary on the stones. Further experi- 

 ments have been carried on more recently in the White 

 Mountains bv Prof. E. Dwight Sanderson, and he also 

 found that Phinotas oil applied to the running streams 

 was eff^ectual in the destruction of the Simulium larvae 

 (see " Controlling the Black Fly in the White Mountains," 

 E. D. Sanderson, Journal Economic Entomology, vol. iii., 

 p. 27, iqio). There still remains, however, much experi- 

 mental work to be done with regard to the effect of the 

 oil upon the fish, the details of the life-histories of the 

 species of Simulium, and the practical methods to be used 

 in applying the oil. 



If Dr. Sanbon's results are confirmed, and the Simulium 



