380 THE OUTGO OF ENERGY 



base of the skull from side to side in a line join- 

 ing the anterior margins of the tympanic mem- 

 branes. (Where possible, a male frog should be 

 selected for this experiment. Males may be rec- 

 ognized by the cushion-like thickening on the 

 innermost digit of the manus, or hand ; the male 

 Eana esculenta possesses bladder-like, resonating 

 pouches connected on each side with the mouth 

 cavity.) After the immediate shock of the opera- 

 tion has passed, stroke the back over the anterior 

 half of the spinal cord. 



Eeflex croaking will be observed. 



The croak reflex can be inhibited by simultane- 

 ous pinching of one of the limbs or other strong 

 stimulation. (Compare page 384.) 



If the experiments on the frog in which the 

 cerebral hemispheres were extirpated were not 

 satisfactory, repeat them on -this frog in which 

 the hemispheres were simply separated from the 

 remainder of the brain. 



These observations teach that very complicated 

 co-ordinated actions are possible in the absence 

 of the large hemispheres. Only simple reflexes 

 are possible when the whole brain is removed. 

 Consequently, the seat of these complicated re- 

 flexes must lie in the brain between the cord and 

 the cerebral hemispheres. 



