In the early days of tuberculin therapy the administration of large doses proved so disastrous that its use was almost completely abandoned. Now, under the leadership of Goetsch, Sahli, Denys, Spengler, Wright, Trudeau, and others, it is again coming into vogue, but all seem to be agreed that it must be given in small doses. The purpose in giving small doses is to avoid a reaction, which is now recognized as harmful to the patient and as influencing unfavorably the subsequent treatment. Sir A. E. Wright does not pretend to increase his dose systematically, but is content if he can keep the tuberculo-opsonic index of his patient "above normal." Except for Wright, most workers look on the administration of tuberculin as a process of immunization of the patient, and hence as the patient's immunity gradually increases they gradually increase the dose. The dose should increase pari passu with