18 PROTECTION OF PLANTS, 1915-16 



end, as surely as a piece of chocolate is yielded up by the "penny-in-the- 

 slot" machine when the right coin is dropped in." (Goodrich). 



Dr. Hans Driesch has said: "Instinctive behaviour is a complicated 

 reaction that is perfect the very first time. This is illustrated by the action 

 of the work bee that leaves the hive for the first time to collect nectar and 

 pollen from flowers, and by the action of the larvae of the Sphex in devour- 

 ing the paralysed crickets in the cells one after another." 



Other Theories of Instinct. 



It is evident that there are many grades of nstinct in the insect world, 

 some simple or primary, others complex or secondary. Primary instincts 

 may be, and probably are, largely tropic in their nature, that is they are 

 reactions or responses to stimuli of various kinds. Secondary instincts, 

 however, are more difficult to unravel, being combinations of tropisms. 

 They occur in most insects, and are specialized in the higher Hymenoptera. 



According to the Neo-Lamarckians, instincts represent inherited 

 results of experience which have become automatic, but the objection to 

 this view is that there is no proof that acquired characters are heritable. 



According to the Neo-Darwinists, instincts are not the results of exper- 

 ience "either at the intelligent or the reflex level," but germinal variations 

 which have been preserved by natural selection. 



Bergson's view is that "instinct expresses a particular mode of know- 

 ledge, differing from intelligence rather in kind than in degree," and evolv- 

 ing along divergent lines from the beginning. 



The vitalistic view of instinct championed by Bergson and Driesch 

 stands opposed to the mechanical theory of Loeb and others. It assumes 

 that there is something in the behaviour of organisms which the mechanical 

 theory cannot explain. This something, called Entelechy by Driesch, 

 is of a regulatory nature, directing the potentialities of the organism in such 

 a way that its activities transcend those of pure machines. Vitalists see in 

 living organisms a unified behaviour in which all changes are correlated 

 to an extent not observed in machines. The living organism is "a self- 

 stoking, self-repairing, self-preservative, self-adjusting, self-increasing, 

 self-producing machine, and cannot be described completely in physico- 

 chemical terms," {Thomson.) 



Bergson thinks that at an early period of the world a "broad current of 

 consciousness penetrated matter" and carried matter along to organi- 

 sation. This consciousness launched into matter is life, and split up into 



