414 PROGRESS OF SCIENCE IN THE CENTURY. 



call them congenital or germinal variations, and 

 there is no doubt that they are transmissible. The 

 precise problem is, whether the modifications of 

 the body can so specifically affect the reproductive 

 cells that the next generation will inherit in some 

 measure the modification acquired by the parent or 

 parents. If summing up, in Galton's phrase, we call 

 the effects of surrounding influences " nurture,^^ our 

 question is seen to be an extraordinarily important 

 one. May the results of nurture be transmitted, or is 

 it the " nature '' alone that constitutes the inherit- 

 ance? 



Widespread Opinion in Favour of Affirmative An- 

 swer. — In fairness we are bound to recognise that 

 the verdict of the practical man, whether gardener 

 or farmer, breeder or physician, is still predominantly 

 in favour of an affirmative answer. 



There is little to be gained by a citation of 

 opinions, there are equally great names on both 

 sides. It cannot be an easy question w^hen we find 

 Spencer on one side and Weismann on the other, 

 Haeckel on one side and Professor Ray Lankester 

 on the other, Sir William Turner on one side and 

 Professor His on the other, and so on. 



The reason why the affirmative position is so 

 widely held is probably threefold: (1) First, that 

 there are many facts which suggest modification- 

 inheritance until they are examined critically. The 

 late Duke of Argyll said that the world is strewn 

 with illustrations, and Dr. Haacke has compared the 

 evidence for the affirmative to the sand on the sea- 

 shore for multitude, yet neither furnishes us with 

 a single grain w^hich will bear analysis. That it is 

 an obvious interpretation we grant, but the obvious 



