OBSERVATIONS ON THE SPINAL INTEGRATION OF STANDING

Abstract

A method of estimating the standing power of spinal dogs is described. The duration of the standing may be timed and a graphic record made of the speed of sinking. These measurements have been made in the case of spinal dogs some months after complete spinal transection. The observations, extending over a period of years, emphasize the importance of the spinal centers in the integration of a posture. These centers are evidently, in the intact animal, very dependent upon higher control, since it is only after the lapse of some months of isolation that segmental integration returns to any marked degree. Judging from the conditions which obtain when standing is maintained for a long period, there is a very close relationship between phasic and tonic phenomena. When the phasic reflexes are active the standing posture is well maintained and, when feeble, the tonus of the legs soon gives way under the weight of the body. The phasic reflexes seem to support and enhance the power of standing in the spinal animal, perhaps by leading to the accumulation of excitable substance in the appropriate arc neurones.