Under the most favorable circumstances, an epidemic, which the well-to-do can afford to make light of as a thing to be got over or avoided by reasonable care, is excessively fatal among the children of the poor, by reason of the practical impossibility of isolating the patient in a tenement. The measles, ordinarily a harmless disease, furnishes a familiar example. Tread it ever so lightly on the avenues, in the tenements it kills right and left. Such an epidemic ravaged three crowded blocks in Elizabeth Street on the heels of the grippe last winter, and, when it had spent its fury, the death-maps in the Bureau of Vital Statistics looked as if a black hand had been laid across those blocks, over-shadowing in part the contiguous tenements in Mott Street, and with the thumb covering a particularly packed settlement of half a dozen houses in Mulberry Street. The track of the epidemic through these teeming barracks was as clearly defined as the track of a tornado through a forest district. There were houses in which as many as eight little children had died in five months. The records showed that respiratory diseases, the common heritage of the grippe and the measles, had caused death in most cases, discovering the trouble to be, next to the inability to check the contagion in those crowds, in the poverty of the parents and the wretched home conditions that made proper care of the sick impossible. The fact was emphasized by the occurrence here and there of a few isolated deaths from diphtheria and scarlet fever. In the case of these diseases, considered more dangerous to the public health, the health officers exercised summary powers of removal to the hospital where proper treatment could be had, and the result was a low death-rate. These were tenements of the tall, modern type. A little more than a year ago, when a census was made of the tenements and compared with the mortality tables, no little surprise and congratulation was caused by the discovery that as the buildings grew taller the death-rate fell. The reason is plain, though the reverse had been expected by most people. The biggest tenements have been built in the last ten years of sanitary reform rule, and have been brought, in all but the crowding, under its laws. The old houses that from private dwellings were made into tenements, or were run up to house the biggest crowds in defiance of every moral and physical law, can be improved by no device short of demolition. They will ever remain the worst.