224 Heredity. 



a. The grey substance of the medulla oblongata has higher and 

 more intelligent functions than those of the spinal cord. It 

 governs certain muscular co-ordinated contractions which do not 

 depend on the will, and which are often unconscious ; these acts 

 are respiration, deglutition, simple exclamation, sneezing, coughing, 

 yawning, and those muscular contractions which constitute the 

 play of the physiognomy. 



If to the spinal cord and the medulla oblongata we add the 

 annular protuberance, removing all the rest of the encephalon, 

 the automatic acts produced are still more remarkable. Animals 

 thus treated utter, when pinched, plaintive cries, having the true 

 expression of pain. A rat with the cerebral hemispheres removed 

 makes a sudden jump when one comes near him, and imitates the 

 ' spitting ' of an angry cat Dogs and cats with the cerebral 

 lobes removed will, if a decoction of colocynth be poured down 

 their throats, make grimaces with their lips as though they would 

 free themselves from a disagreeable sensation. Thus, then, the 

 nerve-centres we have enumerated produce, in the absence of the 

 brain, unconscious sensations of pleasure and of pain, of hearing 

 and of taste. 



If to these we add the tubercula quadrigemina we shall have 

 unconscious visual sensations. A pigeon with the cerebral hemi- 

 spheres removed makes a movement of the head as though to 

 avoid a danger that threatens, when the fist is suddenly brought 

 close to it An experiment first made by Longet shows that the 

 pigeon follows with its head the motions given to a lighted 

 candle. 



All these phenomena are of the same nature as those which 

 depend on the spinal cord, and suggest the same reflections. 

 They are intelligent that is to say, adapted to an end. At bottom 

 they are identical with physiological acts, and differ from them 

 only by this one character, that they are unconscious, or reputed 

 as such. 



3. The same remark also applies to the automatic phenomena 

 dependent on the cerebellum. The function of that organ seems 

 to consist in co-ordinating the muscular contractions which produce 

 the various movements 'a co-ordination which requires infinite 

 science, that is utterly ignored by the mind.' 'I have often,' 



