THE BEHAVIOR OF PROTOZOA 89 



give the motor reflex with no apparent cause. After a time 

 their actions become slower and more sober. Have we any- 

 thing essentially different in the experiments of Mr. Smith? 

 Possibly so, but I cannot convince myself of it from the 

 results described. 



Hodge and Aikins in their study of the daily life of a 

 Vorticella observed that one individual, after having en- 

 gulfed yeast cells for some time, refused them and persisted 

 in so doing for several hours. What this fact signifies can- 

 not be decided from the single observation reported; there 

 are a number of possibilities, and the correct interpretation 

 can be made only after carefully planned experiments. 



There have been few systematic investigations with the 

 end of testing the educability of the protozoa, and while 

 granting the possibility that future work may compel us 

 to modify our conclusion, it may be said that, thus far, there 

 is no unmistakable evidence that the protozoa are capable 

 of forming true habits or of learning by association. 



BIBLIOGRAPHY 



BINET, A. The Psychic Life of Micro-organisms. Chicago, '94. 

 DAY, L. M. and BENTLEY, M. A Note on Learning in Paramcecium. 



Jour. An. Behavior, 1, 67, '11. 

 BELLINGER, O. P. Locomotion of Amoebae and allied forms. Jour. 



Exp. Zool., 3, 337, '06. 

 GIBBS, D. and BELLINGER, 0. P. The Baily Life of Amceba proteus. 



Am. Jour. Psych., 19, 232, '08. 

 HODGE, C. F. and AIKINS, H. A. The Baily Life of a Protozoan. 



Am. Jour. Psych., 6, 524, '95. 

 HOLMES. S. J. The Behavior of Loxophyllum, etc. Jour. Exp. 



Zool., 4, 306, '07. Rhythmical Activity in Infusoria. Biol. 



Bull., 13, 306, '07. 

 JENNINGS, H. S. Contributions to the Study of the Behavior of 



Lower Organisms. Carnegie Inst. Pubs. Wash., '04. The 



Behavior of Paramoecium. Additional Features and General 



Relations. Jour. Comp. Neur. Psych. 14, 441, '04. Behavior 



of Lower Organisms. N. Y., '06. 



