■^06 



NATURE 



[September 24, 1908 



self-induction and capacity the testing instrument is 

 tuned to resonate with the vibration to be measured. 

 The right point is shown, for instance, in the Flem- 

 ing cymometer, by the point of maximum glow in 

 a vacuum tube. From the known capacity and self- 

 induction of the instrument, at this point, its oscillation 

 constant can be calculated, and, therefrom, the wave- 

 length obtained. For a description of these very in- 

 teresting instruments and other valuable information 

 we must, however, refer the reader to the book itself. 



C. C. G. 



TEE SENSES OF INSECTS. 

 The Senses of Insects. By Auguste Forel. Trans- 

 lated by Macleod Yearsley. Pp. xvi + 324; two 

 plates. (London : Methuen and Co., n.d.) Price 

 los. 6d. net. 



COMP.AR.^TI\E psychology as a science is beset 

 with more difficulties than most of its kindred 

 natural sciences. One of the greatest of these difficul- 

 ties is that man, a creature gifted with the most 

 highly developed intelligence, endeavours to interpret 

 and explain the actions of the lesser intellectually en- 

 dowed members of the animal kingdom from their 

 standpoint. However much he may endeavour to avoid 

 assuming an anthropocentric attitude, he must in- 

 variably find himself seated again on his pedestal of 

 intellectual preeminence. He cannot avoid it; it is 

 the only criterion he possesses. This difficulty is 

 never more apparent than when an effort is made to 

 study the manifold activities of that most active of 

 the animal groups, the insects, and especially those 

 families in which social habits have attained such a 

 high state of perfection. In the study of the senses 

 of insects we are necessarily compelled to form infer- 

 ences from our own sensory experiences, and the 

 result is that we not only cannot obtain an adequate 

 conception of their ordinarv sensory powers, but are 

 completely baffled by many organs of an undoubted 

 sensory nature. 



Dr. Forel's work on this subject is not so well 

 known m this country as it deserves to be. This, no 

 doubt, is due largely to the fact that most of it 'has 

 been published in rather out-of-the-way journals. 

 Those students whose interest in the subject has been 

 stimulated by Lord Avebury's work will be grateful 

 to Mr. Yearsley for having performed this " labour 

 of love," as he describes his translation. 



The direct translation and publication in toto of a 

 series of writings of such a nature, however, has its 

 disadvantages. The present volume contains writings 

 which date from the year 1878 to 1906. We have, 

 therefore, not only the author's natural changes of 

 opinion, but also mistakes, in fact, which have been 

 brought about by the gradual growth of entomological 

 inquiry. For example, in the section on hearing, the 

 author states that " only crickets and several other 

 Orthoptera appear to perceive sounds," which, in the 

 light of more recent work of Mayer, Child, and others 

 on the acoustics of certain nematocerous Diptera, is 

 not^ quite correct. Nor does the author devote 

 sufficient attention to the thoracic and crural 

 tympanal organs of the Orthoptera, so well described 

 NO. 20.:;0, VOL. 78I 



by Graber, and of insects of other orders. To a 

 present-day student of entomology a book on the 

 senses of insects is incomplete without fuller refer- 

 ence to the morphological aspect of the subject, not- 

 withstanding the lack of experimental studies. The 

 author truly says, " for the human and animal brain, 

 as well as for its functions, it demands that we shall 

 use anatomical, physiological, biological, and psycho- 

 logical methods." The presence in insects of many 

 problematic organs, which from their histological 

 structure and connections appear to be of a sensory 

 nature, such as, for example, those associated with 

 the halteres of Diptera and the various chordonotal 

 organs which have been described, does not detract 

 from the difficulties which confront the student of 

 these problems. The author pays little attention to 

 these problematic organs, and, in view of the absence 

 of experimental work on them, he is no doubt wise 

 in not discussing them in the absence of facts, as 

 some writers on the subject are accustomed to do. 

 Where he treats with the senses of sight and smell 

 he is more at home ; his experiments are very interest- 

 ing and valuable, and some of his results conclusive; 

 it is in the description of these experiments that the 

 value of the book lies rather than in his, in places, 

 extensive polemical references to some of the work 

 of others. 



The last chapter, on judgment, mind, and reflexes, 

 is one of the most interesting. The author is of the 

 opinion that plastic reaction is primary, and that 

 instinctive or automatic activity which predominates 

 in the insects is secondary. He does not think that 

 instinct can proceed from inherited habits, but that 

 the automatism of all nervous activity, whether by 

 selective heredity or individual habit, is a secondary 

 phenomenon derived from primitively plastic habits, 

 and in support of this he refers to the plastic origin 

 of the slave-making instinct of the species of Formica. 



We venture to think that the book would have been 

 improved had the translator dispensed vi-ith a detailed 

 account of the author's earlier work, the essentials 

 of which might have been incorporated in the account 

 of his later work ; or had the author brought these 

 earlier writings up to date with regard to our pre- 

 sent knowledge of the morphological aspect of the 

 problem, its value to the general reader would have 

 been considerably enhanced thereby. With the excep- 

 tion of sub-oesophageal ganglion (p. 5) where supra- 

 cesophageal is surely intended, and Chalcidites (p. 140) 

 for Chalcidides, there are few mistakes of nomen- 

 clature in the work. C. Gordon Hewitt. 



FORESHORE PROTECTION. 



Coast Erosion and Foreshore Protection. By John S. 

 Owens and Gerald O. Case. Pp. 148. (London : 

 The St. Bride's Press, n.d.) Price 75. 6d. net. 



THIS book consists principally of a reprint of 

 papers on foreshore protection read before ^ 

 various societies, and of articles contributed to maga- 

 zines. 



.Although it does not deal in such a comprehensive! 

 way with the subject of coast destruction and pro- 

 tection as the book on " The Sea Coast " published 



