ZOOLOGY. 369 



have been in a chaotic or amorphous state a something ' without form, 

 and void/ " 



THE SPINAL CORD, A SENSATIONAL AND VOLITIONAL CENTRE. 



The following paper, by Mr. S. H. Lewis, was read at the Leeds Meeting 

 of the British Association, by Prof. Owen : 



The spinal cord, the author stated, was formerly believed to be nothing 

 but a great nerve-trunk; and even now its functions have been limited to 

 the transmission and reflection of impressions. It can conduct impressions 

 to the sensorium and reflect them on motor nerves, producing muscular con- 

 traction; but this is all that physiologists are willing to allow. Doubts 

 having long rested on his mind upon this point, he had made a series of 

 experiments which had led him to a clear conviction; and that conviction 

 and this experimental evidence, he proposed to present. Before detailing the 

 evidence, however, for the sensorial functions of the cord, it will be neces- 

 sary to fix on some broad and palpable signs, such as unequivocally indi- 

 cate the presence of volition. We have such signs in spontaneity of actions 

 and choice of actions. It will scarcely be disputed that an animal manifests 

 volition, and its act is voluntary, when the act occurs spontaneously; I 

 mean, prompted by some inward impulse, and not excited by an outward 

 stimulus. Spontaneity and choice are two palpable characteristics of sensa- 

 tion and volition, and it is these we must seek in our experiments. Those 

 who, for the first time, perform or witness experiments on decapitated ani- 

 mals, find it very difficult to believe that the animals have no sensation; but 

 their doubts are generally settled by a reference to the admitted hypothesis 

 of the brain being the exclusive seat of consciousness. On the strength of 

 this hypothesis the striking facts recorded by Legallois, Prochaska, Yolk- 

 mann, and others, have been explained as simple cases of the reflex actions 

 of the cord. Against this hypothesis of the brain being the exclusive seat 

 of consciousness, I have for some years gathered increasing strength of con- 

 viction, preferring the hypothesis of the sensorium being coextensive with 

 the whole of the nervous centres ; and I have been able, by experiment, to 

 constitute three separate and entirely independent seats of consciousness in 

 the same animal. From the mass of evidence furnished by experiments, all 

 bearing on the same point, the sensational function of the cord acquires, in 

 my mind, the force almost of a demonstrated truth. From that mass, a few 

 cardinal cases may be selected. If they do not carry conviction, there can 

 be little hope in any accumulation of such cases. Place a child of two or 

 three years old on his back, and tickle his right cheek with a feather, he 

 will probably first move his head aside, and then, on the tickling being con- 

 tinued, he will raise his right hand, push away the feather, and nib the tick- 

 led spot. So long as his right hand remains free, he will never use the left 

 hand when the right cheek is tickled, or vice versa. But if you hold his 

 right hand, he will rub with the left. The voluntary character of these 

 actions is indisputable, in spite of their uniformity; they are prompted by 

 sensation, and determined by volition. Let us now contrast the action of 

 the sleeping child, under similar circumstances, and we shall find them to be 

 precisely similar. Children sleep more soundly than adults, and seem to be 

 more sensitive in sleep. I tickled the right nostril of a three-year old boy. 

 He at once raised his right hand to push me away, and then rubbed the 

 place. When I tickled his left nostril he raised the left hand. I then softly 



