454 GEORGES BOHN 



Thus in a single genus we find the principal stages leading from 

 the primitive instinct of solitary wasps to the far more highly 

 developed instinct of social wasps. 



It is to be regretted that the French have almost wholly 

 neglected experimental researches on the higher animals, which 

 have given such fine results in America. The only method used 

 on the higher animals is that of training. 



The paper by Hachet-Souplet ^ is a lecture summarizing the 

 ideas already expounded by the author. In particular, H.-S. 

 reports experiments where he accustomed birds to react in a 

 definite way to a definite variation in illumination. He explains 

 what he calls the law of recurrence, one of the laws of sensory 

 association, and accounts by its means for the supposed rational 

 foresight of birds. Intelligence does not come in until there is 

 a possibility of " persuasion" (see also C.r. Acad. Sci., CL, 

 pp. 238 and 735). 



Besides these accounts of personal investigations, we have to 

 note a certain number of discussions of the problems of com- 

 parative psychology, such as "La genese des instincts esclava- 

 gistes et parasitaires chez les Fourmis, " by Pieron '"^ " L'orienta- 

 tion lointaine," by Thauzies ^\ " L'etude objective des phenomenes 

 cerebraux," by Bohn ^ " Le dressage des animaux," by Drzewina \ 

 and finally, a book by Pieron ''on " L 'evolution de la memoire." 

 This book, published in the Bihliotheque de philosophie scienti- 

 fique, comprises two parts, the one dealing with animals and 

 the other with man. In the former, the author after having 

 indicated the relations of the phenomena of inorganic memory, 

 of hysteresis, for example, with those of psychic memory, studies 

 rhythmic persistances (plant rhythms, animal rhythms, organic 

 rhythms), and dwells at length on the discussion of facts and 

 experiments regarding animal memory, which he classes under 

 three heads: adaptive memory, acquisition of habits, sensory 

 memory. These rubrics correspond to the different methods of 

 research on animal memory, such as the study of the modifica- 

 tion of reactions under the influence of repeated stimulation, 

 the study of the reproduction of movements, and that of the 

 recognition of images. The author devotes only a few lines to 

 the work of the school of Pawlow, although it is generally con- 

 sidered of great importance for the study of associative memory 

 in the higher vertebrates. He insists on the distinction between 



