THE NERVOUS SYSTEM 



271 



fore legs. There are no respiratory movements; the vaso- 

 constrictor tone of the blood vessels is impaired or absent, 

 as are also many other of the most important reflexes. 



But if one leg be pulled gently backward, the animal will 

 bend it again to its normal position under the body. If the 

 toe be pinched, the leg will suddenly be drawn away; and 

 if the skin of the flank be irritated by a bit of filter paper 

 moistened with acid, the paper will be kicked off by the leg 

 of the same side. 



These are all pur- 

 poseful 1 and coordi- 

 nated actions, and 

 make upon the inex- 

 perienced observer 

 the impression that 

 the frog is aware 

 of the stimulus and 

 acts intelligently. 

 But the mere fact 

 that an act is pur- 

 poseful and coordi- 

 nated does not show 



FIG. 111. Section of the cortex of the cerebellum 



(at right angles to that shown in Fig. 110). After 



Ramon y Cajal 



that it is a conscious 

 act ; our movements 

 of respiration, winking, coughing, and sneezing are purpose- 

 ful and coordinated, but we know well enough that they, 

 as well as more complicated actions, may and often do occur 

 in the complete absence of consciousness. One of the first 

 lessons that the student of animal behavior must learn is not 

 to make the mistake of regarding an action as conscious 

 merely because " it looks so" or is purposeful and more or 

 less highly coordinated. 



1 The word f f purposeful " is used here in the same sense as in Chapter VII 

 (p. 70) and does not include conscious purpose in its meaning. We shall see 

 that conscious purpose involves the cooperation of the cerebrum. 



