OLFACTORY REACTIONS IN AMPHIBIANS 627 



worm some distance and finally picked it up, using both the 

 tongue and lips to do so. 



In another trial, the toad was placed in the center of the 

 floor and the worms were distributed in the portions of the 

 box near the walls. The illumination was lateral, thus leaving 

 one side of the box quite dark. Movement of worms in the 

 darker regions of the box were not seen by the toad, even when 

 it was turned toward the worms. "V^Tien a worm moved in the 

 light part of the box, the movement soon attracted the attention 

 of the toad and the characteristic reaction followed immediately. 

 Repetition of the experiment several times with other toads gave 

 the same results. 



When the dungworms were replaced by pillbugs (Oniscus), 

 these were immediately caught when in the light, but not when 

 in the dark. 



Other trials with mealworms, earthworms and dungworms 

 gave like results; only during the periods of illumination was 

 the food sought and then with no discrimination in favor of any 

 particular form. 



Other trials, with very dim daylight as a means of illumi- 

 nating the chamber, gave identical results. If the mealworms 

 or the dungworms were in the darker portions of the chamber, 

 they were unnoticed by the toad. When the box was covered 

 so as to cut off all illumination, there were no movements on the 

 part of the toad; darkness prohibiting entirely any food seeking 

 activities. 



In the lighted portions of the chamber the worms were only 

 seen if in the direct visual field; if somewhat to the rear or to the 

 side of the toads they apparently could not be seen, except when 

 in very vigorous motions. 



3. Ahnorrnal odors and darkness 



In connection with the darkness experiments, trials were 

 made with the same odorous substances that had been used 

 in the preceding experiments. The same individual toads 

 were used as before. Mealworms were treated with appli- 

 cations of oil of clove, carbon bisulphide, and oil of rose gera- 



