On reciprocal innervation of antagonistic muscles. Twelfth note.-Proprioceptive reflexes

The following two reactions, observable in the extensor muscle of the knee, appear not without importance for the reflex co-ordination of antagonistic movements at that joint. They are reactions favourably studied in decerebrate rigidity. The cat is the animal in which, under that condition, my results have been chiefly obtained. The reactions can be observed as follows:—In the decerebrate animal a preparation of the extensor of the knee is so made that by detachment of other muscles, or severance of other nerves, the vasto-crureus muscle, with its nerve-branch from the anterior crural trunk, remains the sole nerve-muscle component intact in the whole limb. The vasto-crureus is one of those muscles which, after decerebration, exhibits the marked tonus characteristic of decerebrate rigidity. This tonus of the vasto-crureus then maintains the knee in an attitude of partial or complete extension. The flexor muscles of the knee, together with all the other muscles acting on that joint, have been paralysed by section of their nerves.