330 Journal of Comparative Neurology end PsyrLology 



The results of this series of experiments when compared 

 with a similar series taken in the light are these : (i) The 

 range of v^ariation in reaction-time is greater in the dark than 

 in the light ; (2) A longer time is required to form a definite 

 habit of entering tlie cage for food; (3) The average time 

 required, e\'en omitting the excessively' long periods, is longer 

 than that required for the analogous experiment in the light. 

 This is true in spite of the greater activit}' of the animal in the 

 dark and the greater freedom with which exploration is made; (4) 

 It follows, therefore, that the number of random movements is 

 much greater in the dark than in the light. This the smoked 

 paper shows to be almost invariably the case. 



Colli hcsions fscni the lour tcst.^. 



In those tests in which onl\- a \'isual stimulus of food 

 was permitted in a situation not previousl\' associated with food, 

 there was no attempt to obtain the food ; it apparently' did not 

 attract attention. Other experiments, particular!}' the choice 

 experiment of test \\\, ga\'e negati\'e results as to the effi- 

 ciency of a visual stimulus when not reinforced b}' other 

 stimuli. 



From the sixtii and se\'enth tests it wa< concluded that, 

 after a situation is once connected with food, it is reacted to as 

 a whole with tlie appropriate movements An odor stimulus 

 of food is then not a part of the situation essential to the reac- 

 tion. 



From the eighth test we found that the situation might be 

 considerably complicated without diminishing the appropriate- 

 ness of the reaction. A situation which presents difficulties of 

 the kind which the animal would meet in its natural environ- 

 ment, is rapidly learned and reacted to almost automaticalU'. 



The ninth test has shown that vision is an important ele- 

 ment in learning the problem, but cannot be the only element, 

 since the problem was learned without it, though more slowl\'. 



after eating the bite or two allowed at each entrance, (b) a little fright and dis- 

 couragement from being repeatedly removed from food. The lengthened time 

 of reaction was often noticed if the experiments were repeated several times in 

 succession, and therefore too frequent repetition was hereafter avoided. 



