HABIT P^ORMATION IN FROGS 319 



Second day. 2.30 p. m. A worm painted with CaClj was placed 

 into the cage ; it was not eaten. I presented in a few minutes 

 a mealworm. It was eaten promptly. In a few minutes I painted 

 a worm with CaClj and put it in the same place where the meal- 

 worm had been picked up, but the worm was not eaten. The 

 frog hopped away in three minutes. Another mealworm was 

 eaten in 15 seconds. 



Third day. I placed a worm treated with CaCl, into the cage, 

 but there was no reaction on the part of the frog. A meal- 

 worm was then presented. It was eaten in 15 seconds. Then 

 I fed an untreated worm. No reaction occurred in 5 minutes. 

 I then fed a meal worm, which was eaten in one minute. In 

 about 30 minutes an untreated worm was placed into the cage 

 without eliciting any reaction on the part of the frog for several 

 minutes. Then another untreated worm was placed into the 

 cage. No reaction was evident for about 8 minutes. Then 

 the worm happened to crawl awa}^ from the frog to the side. 

 When it was about 10 cm. away, the frog made a very feeble 

 effort to get the worm. I then caused the worm to crawl toward 

 the frog from the side. When the worm was crawling under 

 the frog's chin, the frog made another effort to get the worm, 

 but missed it, getting instead a few grains of sand. As the 

 tongue was withdrawn into the mouth the sand was scraped 

 oft' on the jaws, from which it was at once wiped with the fore 

 feet. The frog hopped away in a few seconds. I presented 

 another normal worm. In a few seconds the frog became 

 interested — shown by a slight side twist of the body — but an- 

 other frog in the cage snapped up the worm. 



Fourth day. 10 a. m. I placed a worm treated with CaClj 

 into the cage for over five minutes, but there was no response 

 on the frog's part. I then presented another similarly treated 

 worm. After one minute the frog made a \'ery feeble effort 

 to snap it up, but did not succeed. Since this worm became 

 inactive I presented a third similarly treated with CaClj. After 

 three minutes the frog made six feeble and unsuccessful strokes 

 with the tongue, followed by a seventh strong stroke which 

 brought the worm's head into the frog's mouth. When the 

 worm was about one-third swallowed the frog began to jump 

 about the cage rather violently, a peculiarity of behavior caused 

 probably by the contact of the worm's body (treated with CaClz) 



