Abstract
During the course of experiments previously reported 1 a male cat was prepared with an extensive bilateral lesion probably involving the left side of the eighth cervical segment and the right side of the first thoracic segment of the spinal cord. The lesion was produced on March 26, 1940. At the time of writing, 21 months after the operation, the animal appears to be in excellent condition. Its weight remains constant at about 3.04 kg, which is slightly above the preoperative value. There have been no pressure ulcers. The appetite is good, and although neither micturition nor defecation occurs spontaneously, the output of urine and feces is normal in quantity. Active spermatozoa are produced and are ejaculated in response to appropriate stimulation. Sensory anesthesia and volitional paralysis are apparent below the level of the lesion. Breathing is entirely diaphragmatic. The functional signs are those of complete interruption of the spinal pathways.
In addition to the usual spinal reflexes, which appear in this animal with regularity and vigor, there is occasionally exhibited a mass reflex of exceptional character which I have not seen described for laboratory animals. It is often elicited by rubbing the shoulder region in such a way as to evoke the typical scratch reflex. Upon continuation or intensification of the stimulus, the scratch response gives way to a violent flexor spasm of the muscles of the abdomen, which brings the hind feet into a position forward of the head, with the legs slightly abducted. As the flexor spasm begins, the rubbing of the shoulder region is discontinued, and the subsequent events occur without further external stimulation.
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