Few subjects are of more engrossing importance than the conditions requisite for the physical well-being of the rising generation; and as our embryo men and women spend a very large portion of their lives in school-rooms, it becomes a serious matter to determine whether these nurseries of learning are constructed in such a manner as to consist with the highest possible health standard. The investigations undertaken by Dr. R. I. O’Sullivan and his fellow-committeemen at the instance of the Medico-Legal Society reveal a condition which is truly startling. Oxygen is the life of our life-blood, and, if it is not supplied in the requisite quantity, the human system becomes predisposed to every disease and the foundation of a lifetime of misery is laid. Yet it is notorious that the arrangements of our much-vaunted school buildings go far short of ensuring a sufficient supply of this life-sustaining gas. Much of this deplorable lack of suitable arrangements is the result of ignorance. Many self-constituted sanitarians deem loftiness of ceiling to be the main and, indeed, the only condition required to ensure proper ventilation and a sufficient supply of air. They accordingly build without referenced horizontal breathing-space, in the absurd belief that all foul air ascends and is got rid of, some way or other. Now, the truth, says the report, is “that a lofty ceiling only makes that portion of space above the tops of the windows a receptacle for foul air, which accumulates and remains to vitiate the stratum below.” This is of itself a proof that a scientific supervision of our school buildings is the only guarantee we can have that the health of the children will be properly considered. The quantity of carbonic acid gas given off at each expiratory effort is far in excess of what our amateur sanitarians imagine; and when school buildings are erected without due regard for the diffusion of this deadly emanation, we must not be surprised to see our schools filled with pale and stunted children. In addition to the carbonic acid gas other deleterious exhalations of the human body poison crowded rooms, and are especially the cause of the peculiarly offensive and stuffy odor at which healthy olfactories revolt. Who that has entered one of our city public school class-rooms, between the hours of two and three in the afternoon, has failed to experience this disagreeable sensation? Yet physiology, as well as common sense, tells us that this effete organic matter which is constantly escaping from the lungs and from every pore of the skin is eminently injurious to health. Not only this, but in certain crowded portions of the city the adjoining streets and buildings lend their quota of noxious effluvia to the poisonous agents mentioned. The committee visited “one of the newest, best-arranged, and best-appointed schools in the city, and found it overcrowded and unventilated, tainted throughout the halls, and at