GENESIS, HEREDITY, AND VARIATION. 3G5 



correspond: there is no fixed pattern. But on progressing 

 inwards from the extremities, the distribution of the veins 

 becomes settled — there is a pattern-arrangement common to 

 all persons. These facts imply a predominating control by 

 adjacent parts where control by the aggregate is less easy. 

 A constant combination of forces which, towards the centre, 

 produces a typical structure, fails to do this at the periphery 

 where, during development, the play of forces is less settled. 

 This peripheral vascular structure, not having become fixed 

 because one arrangement is as good as another, is in each 

 determined by the immediately surrounding influences. 



§ 97 e. And now let us contemplate the verifications which 

 recent experiments have furnished — experiments made by 

 Prof. G. Born of Breslau, confirming results earlier reached 

 by Vulpian and adding more striking results of kindred 

 nature. They leave no longer doubtful the large share taken 

 by local organizing power as distinguished from central 

 organizing power. 



The independent vitality shown by separated portions of 

 ventral skin from frog-larvae may be named as the first illus- 

 tration. With their attached yolk-cells these lived for days, 

 and underwent such transformations as proved some struc- 

 tural proclivity, though of course the product was amorphous. 

 Detached portions of tails of larvae went on developing their 

 component parts in much the same ways as they would have 

 done if remaining attached. More striking still was the 

 evidence furnished by experiments in grafting. These proved 

 that the undifferentiated rudiment of an organ will, when 

 cut off and joined to a non-homologous place in another 

 individual, develop itself as it would have done if left in its 

 original place. In brief, then, we may say that each part is 

 in chief measure autogenous. 



These strange facts presented by small aggregates of or- 

 ganic matter, which are the seats of extremely complex forces, 

 will seem less incomprehensible if we observe what has taken 



