272 HARVEY CARR 



embrace the sensory situation at the time, the sensory situation 

 in which the animal lived for several days prior to the act, as 

 well as the intraorganic condition of the animal. The influence 

 of intraorganic factors is evident from four types of facts: — 1. 

 The case of hunger is obvious. 2. Novel situations while running 

 the ma2e may induce effects which persist and exert a disturbing 

 influence after a return to normal conditions. These persistent 

 disturbing effects must be intraorganic. 3. Alterations of the 

 cage environment previous to the performance of the act may 

 exert a disturbing effect. Evidently these disturbing conditions 

 must be retained as some intraorganic condition. 4. The influence 

 of some of these alterations may be cumulative from day to day. 

 These alterations operate in an irregular and sporadic fashion. 

 This generalization is supported by several lines of evidence. 

 1. A few animals in each group are usually immune to the 

 altered conditions. In the majority of experiments the percent- 

 age of animals affected ranged from 50 to 90. 2. Animals may 

 be disturbed in one trial but immune in another. The percentage 

 of trials in which error was present ranges from 30 to 65 for 

 the various experiments. On the average the affected animals 

 were not susceptible to the alterations in one-half the tests. 

 3. An animal may be susceptible to one kind of alteration but 

 immune to another, while the opposite relation will obtain for 

 another rat. Eleven rats were subjected to the following five 

 experiments, — position of experimenter, rotation of cage, position 

 of cage, position of maze, and rotation of maze. Three animals 

 were disturbed in all five experiments, three rats were affected 

 in but four tests, two rats in three tests, two rats in two experi- 

 ments, and one rat in but a single test. Two rats were dis- 

 turbed by the rotation of the maze, but were not affected by 

 a change in the position of the maze; on the other hand, two rats 

 were disturbed by the latter test but were immune to the 

 rotation of the maze. Ten rats were given the following tests, 

 increase of illumination, rotation of maze and environment, 

 cleansing paths, uncovering maze, and rotation of maze. One 

 rat was affected by all tests, three rats were immune to one 

 experiment, four to two experiments, and two to three experi- 

 ments. Three animals were immune to the rotation of the 

 maze and environment, but were disturbed by cleansing the 

 maze; on the other hand two rats were immune to the changes 



