Fig. 16-15. The frog has had the cerebrum removed by a cut just back of the eyes. The cord 

 is intact. Acetic acid has just been brushed on the thigh of the right leg (top left). The 

 right leg flexes and the toes scratch the region which is irritated by the acid (top right). 

 When the posterior part of the body is cut away from the same frog, reflex activity is 

 intact in the remaining part. Here acetic acid is brushed on the right fore leg (bottom 

 left). A moment later that leg flexes first then extends violently; the left leg does likewise, 

 indicating the cross-reflexes operate also when only a small part of the animal is intact 

 (bottom right). 



