272 J. S. NICHOLAS 



5. Experime7its with blinded animals 



The animals were anaesthetized with chloretone and the eyes 

 removed with a pair of fine scissors. After several hours the 

 animals seemed normal and were fed. They were then not 

 fed for a period of five days preceding the commencement of the 

 following experiments. Animal A, which was not normal, due 

 to an inflammation of the external nares, w^as not used in the 

 course of these experiments. The tests were made with the usual 

 test sacks. Results are tabulated in table 1, series 5 (a) and (b). 



The average reaction time in this series is almost the same as 

 that for the normal. All the tests showed that the animals 

 discriminated between the test substances, reacting positively to 

 the earthworm sack. 



In the reactions to moving objects, ten trials were made, all 

 giving the same end result. The animals were quickly attracted 

 by any movement in the water. They would not, however, 

 follow the sand bag, although stimulation was shown by their 

 motor activity. They did follow the earthworm bag and would, 

 if possible, snap and seize it. 



6. Experiments with nose-stopped and blinded animals 



The external nares of the blinded animals were covered with 

 collodion and the animals were subjected to the same trials as 

 those given above. The results are the same for both the mov- 

 ing and the motionless objects. There was no attraction to 

 either object in the motionless series. In the series with the 

 moving object, there was a slight motor activit}^ present but 

 no definite objective. The results are tabulated in table 1, 

 series 6 (a) and (b) . 



7. Partitioned aquarium experiments 



An aquarium was divided into two compartments by the inser- 

 tion of a glass partition which ran diagonally across it, having a 

 slit three-eighths of an inch high between the base of the parti- 

 tion and the concrete bottom of the aquarium. This slit afforded 

 the means by which diffusing substances could pass to the test 



