( Ixxxvi ) 



example— are not variations in the sense of alterations ; are 

 not active changes in constitution, but are permanent diver- 

 sities; they are static, not dynamic. ... All thorough work 

 has led directly to this result : that any species or kmd of 

 organism is made up of a very great number of diverse stocks, 

 differing from each other in minute particulars, but the 

 diversities inherited from generation to generation." These 

 facts were particularly evident in the Protozoa, reproducmg 

 by a single parent, as shown in Prof. Jennings's researches on 

 Paramoecium and Difflugia, both of which were " found to 

 consist of a large number of such heritably diverse stocks, each 

 stock showing within itself many variations that are not 

 heritable." Selection might indeed operate, but it was the 

 selection of diversities that were already present, and thus 

 led to no new steps in evolution. [Just as it was shown on 

 p. Ixxxi that a Bornean mimetic female form of rapilio polyles 

 was present as a very rare variety in Travancore, so it might 

 be held that all mimetic patterns of the species were also 

 present and could be made predominant by selection without 

 requiring any new step in evolution.] " Variations . . . were 

 not variations at all, in the sense of steps in evolution ; they 

 were mere instances of the static condition of diversity that 

 everywhere prevails." 



Well might the author conclude " in these days of plots 

 and spies, the evolutionists might almost feel that the enemy 

 had crept into their citadel and was blowing it up from 

 within" But of course naturalists do not maintain that 

 changes never take place : " they admit that mutations 

 occur " ; that the permanent germinal constitution or geno- 

 type " may at rare intervals transform, as a given chemical 

 compound may transform into another and diverse com- 

 pound." A favourite theory of evolution may be outlined 

 thus : " Organisms forming a multitude of diverse strains 

 with diverse genotypes; the genotype a mosaic of parts that 

 are recombined in Mendelian inheritance; selection a mere 

 process of isolating and recombining what already exists; 

 large changes occurring at rare intervals, through the drop- 

 ping out of bits of the mosaic, or through their complete 

 chemical transformation; evolution by saltations." 



