458 PROGRESS OF SCIENCE IN THE CENTURY. 



cated in the beginning of the experimental study 

 of instinct. This is well expressed in the work of 

 Prof. C. Lloyd Morgan, e.g., in his study (following 

 Spalding) of young chicks hatched in an incubator, 

 away therefore from all parental influence.^ 



Bethe — another careful experimenter — has recent- 

 ly done good service in bringing to a focus the inter- 

 pretation of the behaviour of ants and bees as that of 

 reflex machines or autom.ata, — a return to the posi- 

 tion of Descartes. After intricate meanderings 

 (marked on smoked paper) an ant finds a food-treas- 

 ure ; it returns to the nest and comes back to the spoil 

 with reinforcements; but it is only in the course of 

 many journeys that the circuitous path becomes 

 straightened, as the scent-marked trail is definitised. 

 It seems all " chemo-reflex.'' A strange ant, dipped 

 in a solution of the pounded ants of another nest, 

 is received by its normal enemies with friendliness. 

 The home-coming bees which usually fly to the door- 

 way of the hive, like arrows to their mark, are quite 

 nonplussed if the hive be shifted a few yards aside. 

 Even if the hive be simply reversed they cluster in 

 futile excitement at the back wall. 



In 1889, Yerworn published an account of his 

 experiments and observations on Protozoa in which 

 he showed that most of their actions are reflexes, 

 though some show as it were traces of being impul- 

 sive. A different view was maintained by A. Bi- 

 net :j: (1891), who convinced himself that unicellular 

 organisms exhibit genuine selective actions. But 



* See his Animal Life and Intelligence (revised under 

 the title Animal Behaviour) , also his Introduction to Com- 

 parative Psychology and Habit and Instinct. 



t Psychophysiologische Protistenstudien, 1889. 



t La vie psychique des micro-organismes, 1891. 



