REVIEWS 659 



had been sent home to museum specialists they would have been registered as 

 new species. Possibly he is right and yet too much blame must not be given 

 to those unfortunate but indispensable specialists. Possibly, like most conserva- 

 tive naturalists, they have the conception of a species as a group of animals 

 occupying a definite area, bound together by many constant characters and freely 

 interbreeding, whose constitution is adapted to the environmental circumstances 

 of that area. They would be the first to recognise that most of their specific 

 determinations, especially when they deal with collections of animals from un- 

 explored areas, are and must be provisional and would be ready to modify them 

 as soon as fresh evidence on the subject was available. 



The real enigma in the origin of species is not the origin of slightly different 

 strains within the same stock but the origin of adaptations. On this subject, 

 as on what he conceives to be " Darwin's theory of selection," Mr. Lloyd has some 

 extraordinary remarks to make. It is, he thinks, of the essence of Darwin's 

 theory that variation should be small and should be chaotic, i.e. in all directions. 

 Further, he thinks that natural selection is an attempt to explain the unknowable, 

 i.e. adaptation. 



It may surprise him to learn that Darwin was just as well acquainted with 

 the existence of "mutants" as De Vries and if he did not think that they had 

 been of importance in the formation of new species, it was not on account of any 

 philosophical objections to such an assumption but on account of many weighty 

 practical considerations which are set forth in detail in his works. As to vari- 

 ations being " chaotic," Darwin, who spent a life-time in collecting all the 

 information he could about variation, was in a better position to judge than 

 Mr. Lloyd. He found that there was no part of an animal or plant which could 

 not be made to vary in any direction which man desired, as was evidenced by 

 the whimsical peculiarities of "fancy" strains of domestic animals and plants : 

 and it was a fair inference that if man could always find the variations he wanted, 

 they must occur sufficiently frequently to allow natural selection to modify a 

 species in any direction. 



What hazy metaphysical notions Mr. Lloyd has in his head to permit of his 

 calling adaptation " unknowable," it is hard to guess. Adaptation is part of the 

 present order of nature, just as is the distribution of land and water and we have 

 reasons for believing that neither in its present form has existed from all eternity ; 

 and it is the function of science to explain the present from the past. Mr. Lloyd's 

 philosophical reflections are clothed in what he imagines to be an epigrammatic 

 style but we cannot think that such aphorisms as " Dissent is the outcome of a 

 difference of judgment which is inherent in the dissenter" add anything to the 

 forcefulness of his arguments. 



In conclusion we cannot give Mr. Lloyd better advice than to engage in a 

 renewed and serious study of Darwin's works— more especially that entitled 

 The Variation of Animals and Plants under Domestication— and to weigh 

 carefully the concluding passages of that monumental work before putting forward 

 new ideas on the origin of species- 



E. W. MacBride. 



Sylviculture in the Tropics. By A. F. Brown. [Pp. 309, figs. 96. 8vo.] 



(London: Macmillan, 1912.) 

 This refreshing work differs materially from other modern text-books of forestry 

 issued in this country. Of the latter, all the larger ones sufficiently accurate to be 

 worthy of consideration owe their publication — as does the book under review — to 



