•xvii THE METHOD OF ORGANIC EVOLUTION 363 



higher animals. It is differences of the former kind that 

 do actually characterise the great majority of species ; ^ 

 they affect those organs which vary most frequently and 

 most conspicuously in the individuals of every fresh gene- 

 ration ; and they constitute that " individual variation " 

 on which Darwin always relied as the essential foundation 

 of natural selection, and which his followers have shown 

 to be far more abundant and of far greater amount than 

 he was aware of; and, lastly, they afford amply sufficient 

 material for the continuous production of new forms. 

 Rarely in the history of scientific progress has so large a 

 claim been made, and been presented to the world with 

 so much confidence in its being an epoch-making dis- 

 covery, as Mr. Bateson's idea of discontinuous variation 

 corresponding to and explaining the discontinuity of 

 species ; yet more rarely has the alleged discovery been 

 supported by facts which, though interesting in them- 

 selves, are for the most part quite outside the general 

 conditions of the complex problem to be solved, and are 

 therefore entirely worthless as an aid to its solution. 



Before leaving this part of the subject we may note 

 the extension of definite numerical relations to plants as 

 well as to animals. In dicotyledons we have a typical 

 five-petalled flower or a corolla with five divisions, a 

 character which prevails in irregular as well as in regular 

 flowers, and often when the stamens are not a multiple of 

 five, as in mallows, bignonias, and many others. Some 

 form of five-parted flower prevails throughout many ex- 

 tensive natural orders, and comprises probably a consider- 

 able majority of all dicotyledonous plants. A three or 

 six-parted flower is almost equally a characteristic of 

 monocotyledons, prevailing even among the highly 

 specialised and fantastically formed Orchidese and Iridese, 

 thus again demonstrating how large a portion of the 

 specific modifications of organisms are independent of 

 variations in number, but depend wholly upon variations 



^ Mr. Bateson, however, makes the extraordinary statement that 

 " it is especially by differences of number and by qualitative differences 

 that species are commonly distinguished" (p. 573). Species-makers 

 know too well that, among the higher animals at all events, it is not so ! 



