IT IS accepted that by far the greater portion of infectious foci are found above the clavicle and that these comprise practically all primary foci. These may be divided into four groups: Tonsils, sinuses, throat and pharynx, and teeth. The X-ray is of no diagnostic value in tonsil, throat or pharynx diagnosis, is of value to a degree in diagnosing involvement of the sinuses, and is of great value as a diagnostic adjunct in determining the presence and potentiality of dental foci. For when it is considered that with a full complement of teeth there are present, possibly, thirty-two separate foci, the numerical preponderance of this type of focus, and the importance, therefore, of careful diagnosis is apparent. Rosenow's work following hard upon Hunter's excoriation of “American Dentistry,” has brought about an enforced, albeit reluctant, change in attitude on the part of the dental profession toward “dead teeth.” Devitalization, which had been considered heretofore an elective procedure really presenting advantages in the way of future freedom from pain, has been shown to be, on the contrary, a practice with the most menacing possibilities. Oral radiography that had been resorted to previously, principally to measure comparative success in root canal filling or to note regeneration —if any—in areas of periapical destruction after treatment procedure, now offers broader possibilities and has become a definite part of general diagnosis. That it has not come into still more universal usage may be attributed to a reactionary attitude on the part of the extremely conservative group in the dental profession, who will not concede that a “dead tooth” may be a focus of infection, or that teeth bear any relation to anything but teeth. This attitude has thrown the burden of oral diagnosis in a great measure upon the physician, for, finding a disinclination on the part of many dentists to collaborate in detecting potential oral foci and in eliminating them when found, he has attempted to cover this field with his own. His lack of knowledge of dental conditions has been responsible in many cases for unnecessary sacrifice of teeth or for overlooking very definite sources of infection. Oral diagnosis should be achieved by teamwork between physician and dentist, each recognizing the other's problem and working for the good of the patient. There is an all too prevalent misconception that the reading of dental radiograms constitutes a diagnosis. This is no more true of dental than of other radiograms. The radiologist is a consultant—not a diagnostician—and the radiographic evidence must first be reconciled with clinical and symptomatic findings before a diagnosis may be made. This is where the open-minded dentist who is familiar with focal infection developments, and who will let his judgment be guided by the health needs of his patient rather than by possible lucrative restoration requirements, may bring his dental knowledge to the aid of the internist.