=Tuberculin Tests.= There are two tuberculin tests commonly used, which enable the specialist to diagnose doubtful cases. These are the eye and the skin test. Strictly speaking, the public health nurse has nothing to do with these tests, since they are entirely within the realm of the physician, but she should at least understand their significance. The Von Pirquet, or Skin Test, consists of inoculating the forearm with a drop of tuberculin of a certain strength. A positive reaction is manifest by a slight redness appearing within twenty-four hours and this may persist for a day or two, after which it disappears. This test has no value in the case of adults, since all adults are supposed to possess some slight tuberculous focus, and therefore a reaction has no significance. In the case of children, however, a positive skin test has some value. Children are not as a matter of course supposed to possess tubercular foci, and a positive reaction would therefore indicate that they have become infected. A reaction, however, gives no indication as to the location of the focus—it only proves its existence. The Calmette, or Eye Test, has more importance. A drop of tuberculin is placed inside the lower eyelid of one eye, and if a reaction occurs, it does so within twenty-four hours. The conjunctiva becomes slightly red and inflamed, which condition persists for a day or two and then disappears. In adults as well as children, this is a positive indication of tuberculosis—not necessarily of a mere latent focus, but of a possible lesion which must be watched and guarded against. It gives no indication, however, of the location of the lesion. These tests are useful to specialists in helping them to highly refined diagnoses. Dr. Hamman, however, questions the validity of these extremely early diagnoses, unless they are confirmed by sputum findings. If the bacilli are not found the diagnosis rests entirely with the examiner, and is therefore dependent upon the personal equation. =Registration of Cases.= Most States have laws which require the notification of infectious diseases, including tuberculosis. This means that all physicians are required to report their cases of tuberculosis to the Health Department, filling in a card, more or less complex, in which is set forth the patient’s name, age, address, occupation, and the duration and stage of the disease. In Baltimore, the nurses also are allowed to register their tuberculous patients in this way, with the city as well as the State Health Department. The card used is the same as that used by the physicians, but with this difference—since a nurse is unable to make a diagnosis herself, she is required to place in the corner of the card the name and address of the physician or dispensary responsible for the diagnosis. In this way the authorities are enabled to know how many patients are under the nurses’ supervision, and the sources of the diagnosis.