1897. 



SOME NEW BOOKS. 203 



motive of the collection is the emphasis placed upon unlikenesses and 

 their survival because they are unlike. Moreover, it is not variation 

 that requires explanation, but heredity, for " normally, or origmally, 

 unlike produces unlike." 



The first conclusion of those who studied wild plants was that 

 species were fixed entities, originally created as we now see them, 

 and that, if they varied, it was within narrow limits. With cultivated 

 varieties the systematist had nothing to do, Bvassica oievacea might 

 have innumerable varieties under cultivation, but in nature it was 

 apparently a fixed type. Mr. Bailey, however, refuses to keep the 

 botanist outside the garden-fence, and would consider the forms of 

 B. olemcea — cabbage, cole-wort, cauliflower, and kohl-rabbi — as four 

 sub-species. But, though these and other garden-types, such as 

 parsnips and radishes, maintain persistently the characters impressed 

 on them by the horticulturist, yet the many races of each are in a 

 constant state of flux. Mr. Bailey, as a horticulturist, is so impressed 

 by this universal change, that he considers a new character to be 

 useful to a species simply because it makes it unlike its kin. Bat 

 if it be a just inference that the varieties of the cabbage survive 

 because they are " unlike," it is equally logical to conclude that the 

 wild B. oleracea survives because it is "Uke." A study of plants 

 under both conditions suggests that a constant environment cannot 

 induce the plant to change, but that a plant which meets with 

 •' changed conditions of life " (Darwin) may vary to any extent in 

 response to them. The differences, as Mr. Bailey puts it, " find the 

 places of least conflict, and persist because they thrive best. . . . 

 There are, therefore, as many species as there are unUke conditions 

 in physical and environmental nature." This is only true if 

 " species " stands for any degree of variation. " To Nature, perfect 

 adaptation is the end ; she knows nothing, per se, as species or as 

 fixed types. Species were created by John Ray, not by the Lord ; 

 they were named by Linnaeus, not by Adam." 



The thesis of original variation is based on such individual 

 variations of plants as were discussed in Natural Science, vol. vi., 

 p. 385. " Inasmuch as no two individual organisms ever are or ever 

 have been exactly ahke, so far as we can determine, it seems to me 

 to be the logical necessity to assume that like never did and never can 

 produce like." " It is a more violent assumption to suppose that 

 the first unspeciahsed plasma should exactly reproduce all its minor 

 features than to suppose that it had no distinct hereditary power, and 

 therefore, by the very nature of its constitution, could not exactly 

 reproduce itself." This view is supported by the time it takes a 

 breeder to fix any new character ; five years is perhaps the average 

 period for plants. Too much stress, however, must not be laid on 

 individual variations, which really are nothing more than results of 

 inexact growth and unequal distribution of nutriment, for no organism 

 can be " absolute " in nature; and they do not give rise to varieties 

 so long as the environment is unchanged. If a "species" or " form " 

 be regarded irrespective of these individual variations, then it is true 

 that " like produces like." Consider it as Mr. Bailey does, and it is 

 equally true that "unlike produces unlike." 



The facts of horticulture lead Mr. Bailey to summarise this part 

 of his book thus : — " Unlikenesses in plants are (i) the expressions of 

 the ever-changing environmental conditions in which plants grow, and 

 of the incidental stimuli to which they are exposed ; (2) the result of 

 the force of mere growth ; (3) the outcome of sexual mixing. They 

 survive because they are unlike, and thereby enter fields of least 

 competition." 



