vin DARWINISM AND HOLISM 205 



Nature, why Evolution makes steps in advance on the road 

 on which it is already moving, instead of making incalculable 

 twists and turns, as it might do if its course was merely de- 

 pendent on purely accidental, arbitrary and unmotivated 

 variations. 



That modifications of a certain intimate bodily character, 

 and continued through many generations, may in the end 

 influence the germ-cells and even modify their hereditary 

 structure is easier for us to appreciate than it was for Weis- 

 mann. It is only recently that we have learnt to understand 

 the important functions which the hormones given off by 

 the ductless glands perform in the regulation and balance 

 of our whole animal economy. We now know that the 

 germ-cells, so far from being independent of the developed 

 system of body-cells, have even apart from their reproduc- 

 tive functions a most intimate regulative effect in co-ordi- 

 nating the functioning of the bodily system as a whole. If 

 there is this open door between them, there is no reason why 

 there may not be the reverse influence of the body-cells on 

 the germ-cells.^ 



This question of the way in which non-hereditary modi- 

 fications are conserved brings us to another difficulty 

 which Evolutionists have found it very hard to explain on 

 the accepted Darwinian principles. I refer to the natural 

 selection of small variations. How can small variations 

 be selected and conserved in the struggle of existence until 

 they are marked enough to become specific? To begin 



^ From this point of view the recent experiments of Professor Pavlov 

 on the associative memory of white mice are interesting. An electric 

 bell was rung while the mice were feeding. It was found that a firm 

 association was built up after this process had been repeated 300 times; 

 that is to say, after that the mice looke^d for their food whenever the 

 bell was rung. For the children of these mice a less arduous lesson 

 was necessary: after 150 rings the association was established. For 

 the grandchildren only 30 rings were necessary; while for the 

 great-grandchildren (the third filial generation) only five rings were 

 necessary to establish the association. In other words, the acquired 

 experience of the parents made the acquisition of similar experience 

 progressively easier for their offspring. The results of these experiments 

 are not generally accepted. If these experiments are widely corroborated 

 they will throw a new and most important light on the nature of 

 Evolution as progressive facilitation of experience; in other words, on the 

 hereditary character of educability or psychic experience. 



