94 'Journal of Comparative Neurology and Psychology. 



besides the behavior of the Protozoa and Coelenterata, systematic accounts of 

 behavior in Echinoderms, Rotifera, and the lower worms, together with a general 

 chapter on the behavior of other invertebrates. The work was planned to serve 

 as a reference manual for the behavior of the groups treated. But the exigencies of 

 space compelled the substitution of a chapter on some of the important features of 

 behavior in other invertebrates for the systematic accounts of the three groups men- 

 tioned." Every student of behavior will regret the necessity for this omission. 



The descriptive portion of the book is subdivided as follows: Chapter I deals 

 with the behavior of Amoeba and Chapter II with the behavior of bacteria. The 

 next eight chapters are devoted to the infusoria, the forms on which the greater part 

 of the author's own investigations have been made. The behavior of Paramecium 

 is taken as the type and described in considerable detail. Chapter III includes a 

 description of the normal movements of Paramecium, special emphasis being laid on 

 the adaptive characters of the spiral path followed in the swimming. The mechan- 

 ism of the "avoiding reaction," by which term is designated the reaction originally 

 called by the author the "motor reflex," is fully described. A final section describes 

 the method by which "positive" reactions are brought about. From this chapter as 

 a foundation the author proceeds to a more detailed discussion of special features in 

 the reactions of Paramecium to different stimuli, Chapter IV including the account 

 of reactions to mechanical, chemical, thermal and photic stimuli and the orienting 

 reactions to water currents, to gravity and to centrifugal force. Chapter V is 

 devoted mainly to an excellent account of the reactions of Paramecium to electricity. 

 It also includes a short section on the subject of trichocyst discharge. Chapter VI 

 concludes the account of the behavior of Paramecium, and deals with some of the 

 more general features. The first section treats of the behavior under two or more 

 stimuli, especial attention being paid to the interference of the contact reaction (thig- 

 motaxis) with the reactions to other stimuli. Variability and modifiability of reac- 

 tions are next considered. It is clearly demonstrated that the behavior is not of a 

 fixed character, but subject to relatively wide modifications under certain circum- 

 stances. The behavior during fission and conjugation is briefly described. Follow- 

 ing this there is given a very interesting "composite reconstruction" of the daily 

 life of Paramecium. Finally we have a brief discussion of certain general features 

 of the behavior in this organism. The next four chapters deal with behavior of 

 other infusoria according to the same general plan as is followed in the account of 

 Paramecium, but of course with less detail as to individual organisms. An account 

 of the "action systems" of flagellates, holotrichous, hypotrichous and heterotri- 

 chous ciliates is followed by descriptions of the reactions of representatives of these 

 groups to mechanical, chemical and thermal stimuli. The reactions of infusoria 

 to light receive very full treatment. The general conclusion is that "reactions to 

 light occur in the infusoria in essentially the same way as do the reactions to most 

 other stimuli through the avoiding reaction; that is, by the method of trying move- 

 ments in different directions. The cause of reaction is a change in the intensity of 

 light, primarily that affecting the sensitive anterior end. " There is a brief account 

 of the reactions of infusoria to gravity and centrifugal force. Chapter IX is devoted 

 to an account of reactions to the electric current, and a critical discussion of the 

 various theories of the electrotactic reaction which have been proposed. None of 

 these is found to be entirely satisfactory. Chapter X completes the account of the 

 behavior of infusoria : the topics discussed in it are modifiability of behavior, behav- 



