been in the hand or foot, the muscles of this limb become contracted, more or less rigidly, holding it in a position which is not easily changed, even by efforts of the attendant. Sensation is also often more or less perverted. In this condition of tonic rigidity the muscles remain, to relax usually only with death. The most _characteristic features_ of the disease, however, are the peculiar _clonic exacerbations_, which _convert spastic rigidity_ into _violent and convulsive muscle activity_, so that the limbs and even the frame of the patient are more or less contorted, the muscle exertion being sometimes painful to witness. Notable effects are thus produced; the mouth is peculiarly puckered, and its corners drawn upward and backward by the risorius muscles, giving to the face that peculiar expression known as the “_sardonic grin_.” When the abdominal and flexor muscles of the thighs are involved, and the body is more or less curved forward, this condition is known as _emprosthotonos_; when the muscles of the back especially are involved, with the extensor muscles of the thighs, as _opisthotonos_; and when the body is bent to one side or to the other it is called _pleurosthotonos_. It is said that opisthotonic convulsions occur to such an extent in some instances that the heels touch the head. At all events, the patient’s body is frequently raised from the bed, so that he rests upon the head and feet. Another characteristic feature of the disease is the _reflex irritability_, or _hyperesthesia_, by which these convulsive attacks apparently are produced. Into this condition the patient falls more or less rapidly within the first day after the inception of the disease, and to such a height may it be augmented that the slightest movement in the room, jarring of the bed, or displacement of clothing, even noise or a flash of light, may immediately bring on a convulsion. Rupture of muscles has been reported during some of these violent convulsions. [Illustration: FIG. 18 Characteristic tetanic spasm in a rabbit twenty-six hours after inoculation with pure culture of tetanus bacilli. (Tizzoni and Cattani.)] During the course of this disease the jaws are so fixed that patients speak with extreme difficulty and the tongue cannot be protruded. The mind is clear until the end. The pain is rather the acute soreness due to intense muscle strain. There is spasm of the sphincters, by which urine and feces are often retained. There is nothing characteristic about the temperature, which is seldom much augmented. Attempts to swallow give pain, and are resisted because of the renewed muscle spasm which is likely to follow the irritation inseparable from the act itself. As the result of spasm of the glottis peculiar respiratory sounds may be noted.