An infantryman, wounded at Notre Dame de Lorette, May 9, 1915, by a shell fragment in the right popliteal space, was given a preventive injection of 5 c.c. of antitetanic serum, evacuated to a hospital, May 12, and developed signs of tetanus August 1, with trismus and pains and spasms in the right leg. The disease progressed with dysphagia, stiffness and paroxysmal hypertonia of the legs, especially of the right leg, fixed orthotonus of the trunk, neck hyperextended, arms stiff but able to move. Antitetanic serum was given daily. At the end of eight days there was a marked improvement and the whole course ran to approximate recovery in 25 days from the onset of tetanic symptoms, at which time the man was able to get up and walk on a crutch. The external popliteal nerve had been sectioned, and the foot was in a marked equinovarus. Chloroform was administered for the purpose of straightening the foot, September 2, that is, about five weeks after the apparent end of the tetanus. The first stage of the anesthesia lasted about two minutes, but at this point the trunk and leg muscles passed into a state of diffuse contracture. In fact, a _tetanic syndrome_ took place _in the midst of the anesthesia_. At a time when the corneal reflex was completely abolished, it was still impossible, with the exertion of the greatest strength, to flex the segments of the lower extremities. Moreover, the trunk was stiffly extended and the jaws were in trismus. Tonic and clonic contractions were produced by the efforts made to straighten the foot, and these contractions passed from the right side to the left. The chloroform was now increased and a transient resolution of the muscles was obtained, lasting hardly more than a half minute. As all efforts to reduce the pedal deformity failed, anesthesia was stopped. The contractures and paroxysms lasted a few minutes. The knee-jerks were extremely exaggerated and there was a bilateral ankle clonus. After a brief phase of excitement, the patient emerged from anesthesia, began to talk with his comrades, and ate his usual meal without inconvenience. The chloroform anesthesia had lasted twenty minutes, and 60 grams had been administered. It was now determined to section the tendo Achilles and the tibialis posticus. September 8 the man was chloroformed again and the same phenomena were exactly reproduced. Sixty grams of chloroform was again administered. The tendon resections permitted placing the foot in the proper attitude. Next day the patient was examined neurologically. The skin reflexes were found normal. The Achilles and knee-jerks were somewhat exaggerated, but equal on the two sides. There was no ankle clonus. Sensations proved normal. There was a mechanical hyperexcitability of the muscles of the anterior aspect of the thighs and of the calf.