(From the Wm. H. Maybury Sanatorium (Detroit Municipal Tuiberculosis Sanatoriutm),

When guinea pigs are infected with tubercle bacilli they become allergic. Also, they develop a demonstrable degree of immunity. This, all workers in tuberculosis know. Indeed, the association of allergy and immunity is so close that many have postulated a necessary bond between them. In recent years, however, Rich (1) and several other observers (2) have done work which purports to show that allergy and immunity to tuberculosis have no obligate relation and can be separated-the animal may be deprived of its allergy, without suffering any loss of immunity. These investigators have desensitized allergic guinea pigs by repeated injections of tuberculin, have rendered them non-allergic, and have shown that such animals seem to be immune for several weeks (up to 65 days) after re-infection with virulent tubercle bacilli. Our observations on this question embrace the use of approximately 500 guinea pigs in several series of experiments which have been of two varieties: (1) The desensitization of allergic animals and the study of their immunity and (2) the prevention of the development of allergy by daily injection of tuberculin 2 made prior to infection with virulent bacilli, and continued until the termination of the experiments. The development of tuberculosis in these latter, unsensitized animals was then compared with its development in the normal and the allergic control animals. Tuberculosis in allergic-desensitized animals Briefly and without elaboration of the data, it may be stated that our first and larger group of experiments confirmed in part the impression gained by other workers that immunity persist