344 THE POPULAR SCIENCE MONTHLY. 



NERVOUS CONTKOL OF ANIMAL MOVEMENTS. 



FBOaI THE FEENCH OF M. ONIMUS.* 



(.JINCE the celebrated experiments of Flourens, we know for certain 

 KJ that all the acts of the vegetative life in animals are completely in- 

 dependent of the cerebral lobes, and that an animal deprived of these 

 continues to live as well as before, with only this difference, that it loses 

 all will and instinct. With superior as well as inferior animals the 

 cutting away of the cerebral lobes does not put an end to the move- 

 ments which were possible before ; only these movements take on par- 

 ticular characters. In the first place, they are more regular, and may 

 be regarded as the true normal type, for mental influences do not 

 modify them. The locomotive apparatus acts without restraint, and 

 we may, therefore, say that the movements are more normal than in 

 the normal state. In the second place, when the cerebrum is removed 

 the movements only commence after excitations ; they cannot start 

 themselves. The frog must be put in the water to swim, and the pig- 

 eon thrown in the air to fly. In animals without a cerebrum the physi- 

 ologist can determine such or such an act, limit it, arrest it ; he can 

 foresee movements, and tell in advance what will take place in such 

 conditions, as absolutely as the chemist knows in advance the reactions 

 he will get on mixing certain bodies. 



Another peculiarity of movements that take place when the cere- 

 bral lobes are removed is, their continuation when once commenced. 

 On the earth a frog without a cerebrum, when irritated, makes two, 

 three, or more leaps ; he rarely stops with one. Placed in the water he 

 continues to swim till he encounters an obstacle. The pigeon continues 

 to fly, the duck and the goose to swim. The striking thing about it 

 is, the continuation of the state determined at first by an impulse from 

 without ; and we cannot help associating these facts, about animals 

 deprived of their cerebral lobes, with the characteristic properties of 

 inorganic matter. Put agoing, the animal without a cerebrum contin- 

 ues to move till the exhaustion of the conditions of movement, or till 

 it encounters resistance. Put in repose, it remains inert till some ex- 

 terior cause sets it in motion. It is inert living matter. 



The phenomena we are about to consider are caused either by im- 



1 The importance of understanding the springs of animal movement and the condi- 

 tions of their control is the reason for including the present article in The Popular 

 Science Monthly. It has been translated and abridged, from the Revue Scientifique, 

 for the general reader, but those who wish for more detail in the presentation are re- 

 ferred to Dr. Hammond's Quarterly Journal of Psychological Medicine, for July, where the 

 discussion will be given complete, and where kindred questions are elaborately discussed. 

 Fig. 1 has been inserted to give a general notion of the parts of ^he brain referred to in 

 the article. Ed. 



