37. With the destruction of each part of the central mass there will necessarily be some disturbance of the mechanism; but difficult as may be the task of detecting by experiment what is the normal action of any one part, there ought to be no hesitation in recognizing the persistence of functions after certain parts are destroyed. The spinal cord is anatomically known to be the centre from which the limbs, trunk, and genito-urinary organs are innervated. So long as the mechanism of the actions involving such organs is intact, no removal of other parts will prevent this mechanism from exhibiting its normal action. There may indeed arise, and there has arisen, the doubt whether Sensibility is involved in the action of any nerve centre below the medulla oblongata. But this doubt is founded on the traditional hypothesis respecting the seat of Sensation, and is flagrantly at variance with the logical conclusions of Anatomy and Experiment. 38. Anatomy shows that the structure of the spinal cord is in all essential characters the same as that of the medulla oblongata; and indeed that the whole central axis has one continuous tissue, somewhat variously arranged, and in relation with various organs. Abundant Experiment has shown that the spinal cord, apart from the encephalon, is capable of acting as a sensorial and volitional centre. The striking facts advanced by Pflüger, Auerbach, and myself, have not been impugned;[94] but their interpretation has been generally rejected. We showed that a brainless frog responded to stimulation in actions which bore so close a resemblance to actions admitted to be sensorial and volitional--showed the frog _adapting_ itself to new conditions, and _acquiring_ dexterity in executing actions which at first were impossible or difficult, _devising_ combinations to effect a purpose which never by any possibility could have formed part of its habits--manifesting, in a word, such signs of Sensibility, that no one witnessing the experiments could hesitate as to the interpretation, had he not been biassed by the traditions of the schools. 39. Our opponents argued that in spite of all appearances there were profound differences between the actions of the normal and the brainless animal, and that the latter were due simply to Reflex Action. I also insist on profound differences; but underlying these there are fundamental identities. As to the Reflex Action, two points will hereafter be brought forward: 1°, that _all_ central action is reflex, the cerebral no less than the spinal; 2°, that the hypothesis of Reflex Action being purely _mechanical_, and distinguished from Voluntary Action in not involving Sensibility, is an hypothesis which must be relinquished.