KAFKA'S "EINFUHRUNG IN DIE TIERPSYCHOLOGIE" 477 



problem of the criteria for distinguishing sense fields is not 

 taken up. A special case that is considered is the relation of 

 taste and smell. The differentiation here is on the basis of the 

 topographical relations of the sense organs which lead to func- 

 tional differences. Taste functions in the immediate taking of 

 food while smell leads to the search for food. [In other words, 

 it is a difference of extero and intero-ceptors.] If the question 

 of the relation of taste and smell was to be handled at all, the 

 author should by no means have ignored the work on this topic 

 by C. J. Herrick, Parker and Parker and Stabler. The antennae 

 of insects are held to contain the olfactory organs. Miss Fielde's 

 work on the detailed anatomy of the antennae of ants is quoted 

 with approval (?). In his discussion of the study of smell by 

 extirpation methods, Kafka makes the very valuable suggestion 

 that the presence of inadequate but effective stimuli must be 

 reckoned with both in so far as they may affect cutaneous nerves 

 and in so far as they may arouse activities in taste. The presence 

 of this source of error is very probable where intense stimuli are 

 used [and really can only be thoroughly guarded against when 

 data on threshold sensitivities are at hand.] 



In discussing the factors that cause insects to seek flowers, 

 the author opposes Plateau's odor theory and supports Forel 

 and others who find vision and habit the main factors. The 

 recent work of Lovell furnishes additional confirmation of the 

 truth of this point of view. 



The treatment of vision is well executed. Phototropisms are 

 discussed in detail and are interpreted from the standpoint of 

 "trial and error" rather than from Loeb's point of view. The 

 author points out (page 321) "dass die 'Richtung der Licht- 

 strahlen' an sich ein ebenso 'metaphysisches' Erklarungsprincip 

 darstellt wie etwa die ' Willenstatigkeit,' gegen deren Heranzie- 

 hung gerade die Vertreter der Tropismenlehre so energischen 

 Einspruch erheben. Denn wie die Einstellung eines Organismus 

 durch die Richtung bestimmt werden soil, in der die Lichtstrahlen 

 seine Kor per substance durchsetzen (Sachs), bleibt ratsel- 

 haft * * *." This chapter contains a large number of diagrams 

 illustrating the discussion of the evolution of the invertebrate 

 eye. In the presentation of the much be-labored field of insect 

 color-vision, the author leans toward the interpretation that 

 the behavior in question is guided by brightness only. Kafka 



