448 STELLA B. VINCENT 



may be neglected. In the third part, the animals were required 

 to go to the right or to the left according to a visual clue. Lamps 

 of 10 and 2 c. p. were used as stimuli. The temperature was 

 controlled. After 30 trials punishment was introduced and 

 after 50 trials the 2 cp. lamp was discarded and the discrimination 

 was made between the 10 c. p. light and darkness. The rats 

 had from 93 to 109 trials and only 2 out of 14 animals learned 

 to follow the light. These two animals made percentages 

 ranging from 60 to 100. In five other instances the percentages 

 were rising, although the fact is not mentioned, and probably 

 further trials might have trained these also as Foley's work 

 with sparrows, reported below, shows. The work was stopped 

 too soon. One animal persistently chose the dark way. Many 

 set up position habits. Numbers 4, 5, 13 and 14 went three 

 times as often to the left as to the right and number 12 went 

 four times as often to the right as to the left. 



" The understanding of an organism " the same author says, 

 (34) " is won through an analysis of its motor activities." This 

 analysis falls into two chief parts: first, the conditions which 

 influence the general motor activity positively or negatively — 

 conditions which may be outside or may lie within the organism 

 and second, the study of the organized movements going on 

 under the influence of determined and directed stimuli. " In 

 reality," he says, "the course has been reversed and investigators 

 have begun with a study of organized activities and only here 

 and there have sought to clear up the variability of the reaction 

 to a determined stimulus by reference to the changing conditions 

 of the organism or of the environment especially the temporal 

 environment." By means of a bit of apparatus which is called 

 an aktograph, he records the activities of a series of animals 

 through the entire course of a series of days including days 

 chosen at different times of the year. The apparatus was so 

 arranged as to connect with a Marey tambour and make a 

 kymograph tracing. Among other animals white and gray mice 

 were used. No division of activities dependent upon light and 

 darkness was seen in these animals. The white mice showed 

 16 periods of activity averaging 45 minutes each, the gray 19 

 such periods averaging 37.9 minutes each. These periods were 

 fairly evenly distributed between night and day. He says, "It 

 appears as if the division of rest and activity periods should 



