One by one the diseases which have hitherto defied the skill of physicians are yielding to the persistent attack of modern science. Since the successful treatment of diphtheria by subcutaneous injections of antitoxin serum was demonstrated, it has been confidently predicted that sooner or later all diseases resulting from the action of a poison secreted in the blood by a special and characteristic bacillus would be conquered by similar means. Tetanus has its characteristic microbe, which has been recognized, isolated, described and reproduced by artificial culture. The distinguishing symptom of tetanus is a persistent spasmodic spasm of the voluntary muscles aggravated by light, noise, or other disturbing influences to which the patient may be subjected. These spasms may affect any muscular portion of the body, but when, as is often the case, the maxillary muscles are principally involved, the result of the malady is usually known as "lockjaw."