Tuberculosis is a perfectly frightful scourge to these unfortunate captives, causing not infrequently thirty, fifty, and even sixty per cent of the deaths. This, however, is only in keeping with their frightful general mortality. The collection of monkeys in the London Zoo, for instance, some fifteen years ago, was absolutely exterminated by disease and started over afresh _every three years_, a death-rate of thirty-five per cent per annum as compared with our human rate of about two per cent per annum. Here, it would seem, was an instance where there was little need to call in the bacillus. Brought from a tropical climate to one of raw, damp fog and smoke, from the freedom of the air-roads through the tree-tops to the confinement of dismal and often dirty cages in a stuffy, overheated house, condemned to a diet which at best could be but a feeble and far-distant imitation of their natural food, it seemed little wonder that they "jes' natcherly pined away an' died." But let the results speak. A thorough system of quarantine was enforced, beginning with one of the Vienna gardens, and finally reaching one of its most brilliant and successful exemplifications in our own New York Zooelogical Gardens in the Bronx. All animals purchased or donated were tested with tuberculin, and those that reacted were either painlessly destroyed or disposed of. Those which appeared to be immune were kept in a thoroughly healthy, sanitary quarantine station for six months or a year, and again tested by tuberculin before being introduced into the cages. The original stock of monkeys was treated in the same manner or else destroyed completely, and the houses and cages thoroughly cleaned and sterilized or new ones constructed. Keepers employed in the monkey-house were carefully tested for signs of tuberculosis, and rejected or excluded if any appeared. Signs were posted forbidding any expectoration or feeding of the animals (which latter is often done with nuts or fruit which had been cracked or bitten before being handed to the monkeys) by the general public, and these rules were strictly enforced. At the same time the houses were thoroughly ventilated and exposed to sunlight as much as possible, and the animals were turned out into open air cages whenever the weather would possibly permit. As a result the mortality from tuberculosis promptly sank from thirty per cent to five or six per cent. In our Bronx Zoo, for instance, it has become decidedly rare as a cause of death in monkeys, no case having occurred in the monkey-house for eighteen months past. What is even more gratifying, the general mortality declined also, though in less proportion, so that, instead of losing twenty-five to thirty per cent of the animals in the house every year, a mortality of ten to fifteen per cent is now considered large.