620 JONATHAN RISSER 



toads confined in a large metal pan. In this way the animals 

 were kept within bounds but were still allowed much freedom 

 of movement. 



3. Experiments 



The first experiment was made to determine whether choice 

 was made between two forms of food with specific odors. Pre- 

 vious to the trials earthworms had been fed freely to the toads, 

 and it might be supposed that because of the peculiar odor of 

 the dungworm, the latter would be refused as food. 



Toads No. 1 and No. 2 were in the box in which the experi- 

 ments were conducted before the dungworms were introduced. 

 Toad No. 1 saw the worms soon after they had begun to crawl. 

 It quickly hopped toward the worms and attempted to snap up 

 the nearest worm. The attempt was unsuccessful and the lips 

 were wiped with the forefeet. Sandgrains on the lips evidently 

 produced a mechanical stimulus which was followed by the 

 wiping. 



The dungworms were then freed of all the adhering sand 

 and again placed in the center of the box. Although the move- 

 ment of the worms was sufficient to attract the toads, no further 

 attempt was made to take the worms. When a mealworm larva 

 was put in with the dungworms, it was quickly snapped up by 

 the nearer toad. No. 1. 



Dividing a dungworm then into a number of pieces, these 

 were placed in a shallow vessel before the toads. Into the 

 vessel there were also dropped two mealworm larvae. From the 

 mass of wriggling pieces one of the mealworms was immediately 

 selected and swallowed. Upon the dorsal surface of the other 

 mealworm a drop of oil of pennyroyal was now placed; the meal- 

 worm with the oil was also quickly taken. Toad No. 2 made 

 several unsuccessful attempts to take the remaining dungworm, 

 but abandoned the dungworm, taking later some mealworms 

 that had been put in the box. Similar trials with two other 

 toads gave like results, leading to the conclusion that the dung- 

 worm is not used as food under normal condition, a conclusion 

 that was subsequently shown to be false. 



