2l8 



NA TURE 



[January 4, 1900 



-nisesand clearly points out the obvious difficulty that the 

 resemblances in pattern are not to be explained by her 

 hypothesis. 



Similar bias is shown in the prominence given to un- 

 important and often partisan statements ; while the 

 original evidence on which an opposite conclusion has 

 'been based is neglected or barely alluded to. 



Thus, referring to the variable coloration of cater- 

 ipillars, we read on p. 147 : " According to recent re- 

 search, it is not so much the colour of the environment 

 which directly affects the larv£e as the intensity of the 

 light " (see Garbowski). To the conclusive experiments 

 upon which an opposite contention is based no allusion 

 is made, the bias of the writer permitting nothing more 

 than a vague reference to " popular books besides those 

 already mentioned." But, on the strength of the state- 

 ment quoted above, we are treated with reflections upon 

 the errors of a simple explanation in biology. 



Again, on p. 325, in reference to the artifically pro- 

 duced variations in the colours of butterflies, we are told 

 that " competent entomologists {e.g. Garbowski) are of 

 opinion that the new colours have little or no phylo- 

 genetic importance," without the slightest indication that 

 highly competent authorities have given very good reasons 

 for an opposite conclusion. In fact, if the writer agrees 

 with an authority, it is sufficient to quote his opinion 

 without his reasons, and, above all, without any of the 

 reasons which point in another direction. 



The references to Piepers' easily answered and often 

 superficial objections to the theory of mimicry (pp. 

 316-321) are given at considerable length, and the reader 

 unacquainted with the subject might well suppose, from 

 the writer's concluding remarks, that serious difficulties 

 had been raised. 



Ill a similar spirit the writer speaks of " the (by hypo- 

 thesis) well- protected Heliconidae" (p. 149), thus assum- 

 ing an assumption on the part of those who seek an 

 interpretation based upon natural selection, and neglect- 

 ing the considerable body of evidence, direct as well as 

 indirect, which has been brought together. 



The use of the contemptuous " so-called " occasionally 

 recalls the jest about the " so-called nineteenth century." 



The statement of the procedure of the Darwinian 

 school (p. 306), in attempting to solve the problems of 

 colour, is the merest travesty, quite unworthy of serious 

 comment. 



Apart from the obvious bias ot the writer in dealing 

 with natural selection, of which numerous other examples 

 might have been adduced, the work is likely to be useful. 

 The most interesting and valuable parts are those dealing 

 with subjects which the authoress has herself investi- 

 gated, such as the structural colours of birds' feathers. 

 The book is, in fact, not a well-balanced and judicial 

 account of the subject, "Colour in Nature," but an inter- 

 esting exposition of those parts of her subject with which 

 the authoress is in sympathy, other parts being either 

 distorted or omitted. In the former category would 

 doubtless be placed the interpretation of external colour, 

 as the expression of internal structure, of which a single 

 -example is given on p. 226, and it is therefore remark- 

 able that no reference is made to the numerous examples 

 which the late Alfred Tylor was accustomed to explain in 

 this manner. 



NO. 1575, VOL. 61] 



The book is clearly printed, with few printer's errors, 

 and the small number of simple illustrations sufficiently 

 explain the writer's meaning. E. B. P. 



THE GROWTH OF ANIMAL AND VEGETABLE 



ORGANISMS. 

 Experimental Morphology. By Charles Benedict Daven- 

 port, Ph.D., Instructor in Zoology in Harvard Uni- 

 versity. Part 2. Pp. xviii-l-281 to 508. (New York: 

 Macmillan Company ; London : Macmillan and Co., 

 Ltd., 1899.) 

 nPHE second part of Dr. Davenport's work— the first 

 -A- part appeared two years ago and was noticed in 

 Nature, October 14, 1897— deals exclusively with the 

 effect of chemical and physical agents upon the growth 

 of animal and plant organisms. In the preface the 

 author draws attention to the importance of the study of 

 the conditions which affect growth. "The possibility 

 of increasing the human race beyond limits that are not 

 far off depends upon a better knowledge of the conditions 

 of growth. The reader has only to consider that the 

 world's supply of 2500 million bushels of wheat, 2000 

 million bushels of maize, 90 million tons of potatoes, and 

 its untold millions of tons of beef, pork, and fish are re- 

 produced each year by growth." This importance has 

 recently been emphasised by the remarkable result of 

 Sir William Crookes' researches into the statistics of the 

 world's wheat supply as set forth in his presidential 

 address at the Bristol meeting of the British Association, 

 and the controversy to which that address has given rise. 

 Dr. Davenport selects as his definition of growth " in- 

 crease in volume," a definition which is by no means safe 

 from criticism. Although we all think we understand 

 what is meant when growth is spoken of, biologists have 

 been by no means in agreement as to how exactly it 

 should be defined. Thus, as the author points out, while 

 Huxley spoke of growth as "increase in size," Sachs 

 regards the volume increase as necessarily intimately 

 associated with change of form, while Pfeffer takes the 

 qualifying part of Sachs' definition, and defines growth as 

 change in form only, and this is accepted by Vines, who 

 adds: "accompanied usually by increase in bulk." To 

 us this definition appears far more satisfactory, even if it 

 is associated with the idea of development, than the 

 more limited definition adopted by Davenport. In the 

 animal organism especially is it difficult to exclude the 

 idea of change of form in association with growth, nor 

 does it seem reasonable to place a mere swelling due to 

 imbibition of water or to distension with gas upon the 

 same footing as a new formation of bioplasm. 



The book before us is, however, almost entirely con- 

 cerned with vegetable organisms, in which, no doubt, the 

 imbibition of water plays a much more important part 

 in the process of growth than it is apt to do in animals. 

 And as a matter of fact the percentage of water in many 

 animal embryos undergoes a steady decrease as develop- 

 ment and growth proceed. 



With regard to the effect of chemical agents upon 

 growth, one of the most interesting parts of the work is 

 that dealing with the supply of nitrogen to growing plants, 

 whether it be offered to them in the form of a salt 



