184 



KNOWLEDGE. 



[AoGUST 1, 1895. 



their adaptability nor their inadaptability to their 

 environment. 



For all that, the word "mimicry" does, as Mr. Miller 

 observes, imply conscious selection on the part of the 

 insect, though I feel connnced all modern writers have 

 employed the term merely in a metaphorical sense, and 

 because they could find no better. Can Mr. Miller propose 

 a better one ? 1 do not think we have quite the right one 

 anywhere in our language ; but so that future misunder- 

 standings might be avoided, would it not be well to coin 

 one '? — one made expressly for the purpose, and having no 

 other outside meaning, so that misinterpretation would be 

 impossible. Might I suggest such a wordas"ensemblance," 

 and instead of speaking of one insect mimicking another, 

 say that it " ensembles " it ? 



Yours faithfully, 



Alfred .J. Johnson. 

 Baldmere, -July 18th, 1895. 



To the Editor of Knowledge. 



Sir,— In reply to your correspondent, Mr. Miller, I beg 

 to state that my article on the above subject was intended 

 to be simply a brief and popular account of the work done 

 by Darwin and Wallace, and further elaborated by Poulton 

 and others. That many difficulties arise in discussing 

 these problems is well known, and many of the difficult 

 points of natural selection are still unexplained. In fact, 

 many biologists at the present time simply adhere to the 

 theory of natural selection as a working hypothesis because 

 it is the one which is most compatible with known facts, 

 not because it will explain everything. 



Mr. IMiller objects to the term " mimicry " in that it 

 implies conscious effort on the part of the mimicking 

 insect. But the essence of the theory of natural selection, 

 as opposed to the older theory of Lamarck, is that there is 

 no conscious effort on the part of the individual, but that 

 an accidental resemblance, at first slight, becomes in- 

 creased in successive generations by hereditary transmission 

 of peculiarities to the offspring, and by the survival of the 

 fittest, those more nearly resembling the mimicked and 

 protected species surviving. 



Again, Mr. Miller says it will be seen from my paper 

 that " the inferences drawn from the facts related are that 

 those butterflies which are thus protected survive, while 

 those that are unprotected perish, or at least are liable to 

 destruction." 



Because it is a fact that certain insects so nearly 

 resemble their surroundings or other insects that it is 

 almost impossible to distinguish them, and that they are 

 thus passed over or avoided by their enemies, it does not 

 foUow that protection of this kind is ntxef^sanj — as Mr. 

 MiUer says I " seem to say " — for the preservation of the 

 life of every insect. Protective resemblance, warning 

 colours, and mimicry are not the only means by which an 

 insect escapes destruction. There are others, amongst 

 which the power of rapid flight, and habits of concealment, 

 especially in the daytime, might be mentioned. Moreover, 

 there are many insects which do not require protection. 

 Giving to the fact t!;at they have few enemies in the localities 

 where they exist. 



Finally Mr. Miller says : " What has all this to do with 

 the origin of species '? " I fear it would take several whole 

 numbers of Knuwledge to answer this question. I can 

 only refer Mr. Miller to a certain book on the subject by 

 one Charles Darwin. 



Yours truly, 



C. F. Marshall. 



Sc(cn« Notf. 



— ♦ — 



The Society for the Protection of Birds has sent us two 

 new pamphlets, one on the owl, by Mr. W. H. Hudson, and 

 another on the bird of paradise, by Mrs. F. E. I^emon, the 

 honorary secretary of the society. The fact that owls of all 

 kinds are extremely useful as destroyers of rats and mice 

 is becoming gradually recognized by farmers and game 

 preservers, and it is encouraging to learn that several 

 county councils have already included m their lists of the 

 eggs of birds to be specially protected under the new Act 

 those of the owls. There is, however, as Mr. Hudson 

 points out, a barbarous machine called the pole trap, 

 which, although intended to catch hawks, is, nevertheless, 

 equally destructive to owls, and until the setting of this 

 trap is forbidden by law, owls will never become plentiful 

 in this country. The leaflet on the bird of paradise is an 

 appeal to women throughout the world to discountenance 

 the sacrifice of this marvellous and beautiful bird, which 

 is daily becoming rarer , by refusing to wear or purchase 

 their feathers. 



KottcfS of Boolts. 



Till- Srii'ncc and Art of Breadmakimj. By William Jago, 

 F.I.C. (Simpkin, Marshall & Co.) Mr. Jago has for many 

 years devoted special attention to the chemistry and analytic 

 and practical testing of wheat, flour, and other materials 

 employed in breadmaking, and is therefore well qualified 

 to undertake the writing of a book on the science and art 

 of breadmaking. The present volume is, however, only an 

 extension of the author's former book on the same subject ; 

 but as many additions have been made, the present volume 

 forms a valuable compendium of our knowledge of this 

 important industry. The book is, moreover, complete, 

 inasmuch as the author has taken pains to include in the 

 introductory chapters so much elementary chemistry and 

 physical methods of analysis as will enable the reader to 

 follow the more specialized sections which follow. The 

 chapter on the enzymes is exceedingly well written, and is 

 well up to date ; but we must object to the author's word 

 " diastasis," which he has coined for diastasic action. 

 Surely, if a new word is needed, diastalysis would be more 

 accurate. We note further, under the heading of substances 

 inimical to diastasis, no mention among the usual preserva- 

 tives, such as boric and salicyUc acids, of "formalin," 

 which has recently been introduced as a food preserva- 

 tive. The more technical portions of the book may be 

 somewhat out of the scope of many of our readers, but 

 should prove of value to the practical baker and 

 confectioner, as the author has devoted considerable 

 space to the discussion of modern breadmaking plant, 

 and to the best methods of bakehouse design. After 

 the recent strictures passed by Dr. Waldo and others 

 upon the unsanitary condition of London bakehouses, it 

 seems essential that some such book as this should be in 

 the hands of those concerned in the erection or manage- 

 ment of bakehouses, and as we understand considerable 

 improvement has been brought about in Bristol as the 

 result of the agitation, we hope that all interested in this 

 subject will get Mr. Jago's book, so as to be posted up in 

 the details of design which are so essential in securing 

 convenient and sanitary bakehouses. The last four 

 chapters are devoted to the methods of analysis of bread, 

 flours, malt extracts, and other materials used in bread- 

 making. The whole book is exceedingly practical in its 

 scope and treatment, and great pains have been taken to 

 bring the subject well up to date. 



