The degree of success which may attend our crusade against tuberculosis will largely depend upon the wide diffusion of the knowledge of its communicability by means of the sputum dried and powdered and floating in the air as dust, and the intelligent persistence with which the morbid material may be safely cared for at its sources. The resolute avoidance by consumptives of the not only filthy but dangerous practice of spitting upon floors or streets, or anywhere else except into proper receptacles; the use of receptacles which may be and are frequently and thoroughly cleansed, and, best of all, of water-proof paper cups, which with their contents may be burned; or, when circumstances require, the receiving of the dangerous material on cloths or Japanese paper napkins, which may be destroyed by fire, and not on more valuable handkerchiefs on which the sputum is allowed to dry while in use or before disinfection and washing; scrupulous care by others of the sputum of those too ill to care for it themselves--these are the comparatively simple means from which we may most confidently expect relief. The details of these precautions and their adaptation to the special circumstances of those suffering from the disease can be most wisely left to the physician, and though of paramount importance, need not further engage our attention here. To the consumptive himself these measures are not without a vital significance. For his chances of recovery may be in no small degree diminished if he be more or less constantly liable to a fresh infection from material which he has once got rid of, and which should have been destroyed. The great volumes of fresh, moving air which we encounter out-of-doors in properly cleansed streets usually so greatly dilutes the dust, of whatever kind, that little apprehension need be felt from its presence. When, however, in crowded cities, the streets are, as is nearly always the case, save for a few favored localities, filthy, and but fitfully cared for; when choking dust clouds must be encountered by the citizen during the haphazard and slatternly essays at cleaning made by untrained and irresponsible sweepers; we cannot ignore a danger from street dust which may well incite grave apprehension. The citizen can, if he must, run from the presence of cloud-enwrapped machines furiously whirled along half-sprinkled pavements; he may avoid a block on which the hand-sweepers, in the absence or in disregard of rules, ply their nefarious brooms over unwet surfaces, because too indolent or indifferent to sprinkle them--these things he can do if he be not willing or ready to apply the citizen's remedy for municipal misrule.