BEHAVIORISTIC STUDY OF THE RAT 
39 
balloon attached to the end, but in every case, some time before 
a record was taken, either the rat destroyed the tube by biting a 
hole through it, or else was destroyed itself by asphyxiation. 
The possibility of gastrostomy was considered-—that is making a 
small hole through the wall of the abdomen and introducing the 
Fig. 20. Hunger Contractions of the Dog’s Stomach Hours After a Meal 
A, Outline of bismuth coated balloon in stomach between the gastric contrac¬ 
tions; B, outline of balloon at the height of a hunger contraction (Rogers and 
Hardt) 
balloon into the stomach that way, but it was feared that the 
effects of the operation which are necessarily quite severe in such a 
small animal, because of the difficulty of handling such small 
parts, would too greatly modify the behavior to make the experi¬ 
ment practicable. 
