162 THE MENDEL JOURNAL 



assault. The right and left are in possession of the 

 Mendelians, the centre has been reconnoitred and the attack 

 is beginning. But it is here that the conflict must . 

 be necessarily prolonged, on account of the difficult 

 nature of the country to be conquered. For it is 

 here that the great challenge must be made and 

 accepted, as to whether evolution is wholly a matter 

 of that organic advance which would result from the 

 blending in successive generations of miimte, barely 

 perceptible variations, existing simultaneously in large 

 masses of individuals ; or whether it is wholly a matter 

 of more or less irregular advance, sometimes small, 

 sometimes great, due to the spontaneous appearance in 

 a single individual of a mutational character or " sport," 

 and which in its inheritance, through succeeding genera- 

 tions, segregates cleanly and definitely, from its opposite 

 or allelomorphic factor, already present in the race ; 

 or whether evolution is partly due to the one and partly 

 to the other. The existence of selection and elimination, 

 without which there could be no evolution, by either 

 method, is defended by both armies. 



The battle of the future which is to be fought between 

 these two armies therefore turns upon the nature of 

 " Intermediates." And it is along this range of biological 

 hills that the Biometrical centre is concentrating. 

 Do these intermediate stages between the two 

 extremes of a character necessarily manifest the 

 existence of gametic blending, or do they represent 

 simply a series of segregable grades ? That there do 

 exist phenomena which at a first examination and in the 

 absence of any extended experimental knowledge would 

 justify us in the belief that they indicate the existence of 

 blended characters is not denied. But the Mendelians 

 assert that the appearances are false, that they need 

 re-investigation by experimental methods, and that our 

 present knowledge renders it easy for us to conceive of the 

 existence of segregation without there being any obvious 

 manifestation of its existence. The Biometricians impliedly 

 maintain that the existence of intermediates between 

 any two extremes of a character is inconsistent with the 

 segregation of those two extremes, and also with the 

 segregation of the intermediates themselves. And, 



