FUNCTION OF VIBRISSAE IN BEHAVIOR OF WHITE RAT 21 



evident but unless it should prove to be connected with the 

 vibrissae it will not be discussed in this place." 



In order that there could be no charge of temporary disturbance 

 the group of rats without vibrissae which followed these had 

 their vibrissae cut from birth. 



Experiment III. Rats with vibrissae removed from birth. The 

 rats used in this experiment were born in the laboratory the first 

 week in October. They were always kept in the room where 

 they were used and always fed by me. They were three months 

 old when they were first put upon the maze and in perfect 

 condition, three males and three females. Their vibrissae which 

 grew very rapidly were cut twice a week from birth. 



Behavior: — This was very similar to that of the set preceding 

 except that there was not the same timidity in venturing out 

 upon the maze, nor the same slowness in traversing it. The 

 animals flattened their bodies close against the maze and crawled. 

 ■ At first they kept to the middle of the path a characteristic 

 feature in the work of this group, but later they went from side 

 to side of the pathway always nosing for edges and as time wore 

 on walked the edges. They hung over the sides as if looking 

 below but went steadily to work and learned the maze in almost 

 as good time as those of group two. As a whole they kept far 

 more to the middle of the path than those of the other groups. 

 They always preserved somewhat of the flattened crawling gait 

 and never while they were being used lifted themselves high and 

 ran confidently and with heads up. 



Summary of the results of Experiment III. 



Average errors in the first twenty-five trials 44 



Average errors in the first trial 8 



Average time of learning (trial) 22 



Average time of the last ten trials in learning 18.5 sec. 



Average time of the last of these trials 7.5 " 



Slips and falls 72, average 12 



As will be seen the average time of the last ten trials is longer 



"Note: — In basing my conclusions upon these figures I have not neglected the 

 mean variation. It has not only been carefully computed but in many cases has 

 been carefully plotted for individuals and for groups. As between groups, however, 

 the variability is not altogether a matter of chance and since the question which 

 arises is one which does not concern this problem the figures are not given here. 

 In another paper reporting a long series of experiments already finished the whole 

 problem will be treated. 



