THE condition of muiscular rigidity consequent upon decerebration, described by one of us previously in this Journal' forms as was then shown an excellent field for the examination of some phenomena of inhibition. We have in the present work attempted to trace the path of nervous conduction involved in some of the inhibitions that can be evoked under "decerebrate rigidity." METHOD. Our observations have been chiefly upon the cat. also on the dog and the Macaque monkey. The preliminary operation

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... and the decerebration were always carried ouit unider comiiplete aneesthesiadeep chloroform anid ether narcosis. Severe loss of blood was guarded against by thread loops placed round the caroticls controlling those arteries if necessary. The cerebruim was removed completely, anid with it was taken the whole nervous axis in front of a transection midway down the anterior corpora quadrigemina. Artificial respiration was only occasionally found necessary, and then for no long time. The animal wvas after decerebration freely sltung with its vertebral axis horizontal: its temperature was maintained by careful adjustment of hot water tins. After decerebration the administration of chloroform was discontinued. I. Inhibition by electric excitation of the spinal cord. Method. A portion of the hinder thoracic or of the lumbo-sacral region of the cord was exposed in the vertebral canal. The spinal roots of the exposed portion were severed outside the dura mater: this was 1 Vol. xxii. p. 319. 1898.