No. 481] NOTES AND LITERATURE 



43 



pen are studies of the reactions of Metridiuin and of rotifers. Nor 

 have his investigations been limited to the animal world alone for 

 groups on the border lines such as the flagellates and liiiet<Tia have 

 also been included. All students of these groups and especially 

 investigators of animal behavior and workers in the field of eoni|)ara- 

 tive psychology will Gjid cause for congratulation in the fact that 

 Professor Jennings has taken this opportunity to restirvey the whole 

 field of his experimental work and to summarize and restate his con- 

 clusions in this most important field of research. While many studio 

 in this field have been made primarily from the standpoint of the 

 psychologist, or have been of a desultory character, or are but partial 

 in scope, the work summarized in this book has been dominated by 

 the broadest scientific spirit, has been conducted with the greatest 

 care and thoroughness, has included in its scope all possible avenues 

 of approach to the analysis of animal behavior, as exemplified in the 

 simplest organisms, and has been carried through to a stage of com- 

 pletion where fundamental generalizations are possil.h-. Thv work 

 of others in this field whether in a,<:recinciit or not. with the author's 

 conclusions, is treated with liillne» and tainic-. 'i1ie hook thus 

 becomes an exemplification of the value of intensive r(\search, an 

 indispensable authority for any who wish to become familiar with the 

 latest results in the field of animal psychology. As illustrative of the 

 thoroughness with which the analysis has been carried out we find 

 that in Paramecium the structure and the normal movements are 

 described and correlated, and the reactions to chemical and mechanical 

 stimuli of various sorts determined, the ab-sence of reaction to liiiht 

 but the sensitiveness to the ultra-violet rays noted, as ar<' also the 

 reactions to heat and cold, to induction shocks and a constant current 

 of electricity, to water currents, gravity, and centrifugal force. The 

 relation of these actions of orientation to other reactions is carefully 

 analyzed. The behavior of Paramecium in daily life in the aquarium, 



