The enormous literature at the disposal of the naturalists permits executive officers to formulate a plan of housing and feeding with fair accuracy for each kind of animal, but of course it is rarely possible to obtain in sufficient quantity the natural food (_e.g._, ants for anteaters). In so far as food is concerned it seems that with a few exceptions like the one just mentioned, the substitutions made at the zoological gardens are nearly satisfactory. The elements in which the captive diet is poor are the inorganic salts and vitamins since Dr. Corson-White, some of whose work is included in a later chapter, has shown that for those animals which our statistics indicate as most prone to have rickets and osteomalacia, the available phosphorus and calcium are low, and one vitamin was also below the desired quantity. In this regard, however, I am not at all convinced that diet alone will suffice to explain these degenerative osseous diseases; I shall take this up more fully later. Careful inspection of all food should be made and cleanliness (sifting of cereals, protection of meat from flies, etc.), is indispensable. The mortality among our carnivora has materially decreased since the horse meat after butchering was placed in covered galvanized iron pans. There are many problems of feeding, too numerous to be covered in a survey of this sort, which must be solved, and it is a credit to superintendents that this they have studied carefully. There are two problems in the management of animals upon which much difference of opinion exists, namely the heating of houses and the material of which cages are made. It seems to be the practice in many gardens to keep animals very warm. Dr. Chalmers Mitchell states unqualifiedly that adult animals do not have to be kept warm, and that even an equable temperature is not demanded, variations in temperature having a distinctly stimulating effect. However he maintains that they should be kept dry and must be supplied with a shelter. This is in accord with the experience at the Philadelphia Garden, since for many years we have allowed access to the open air all winter to every animal that could stand it. A large group of macaques has now lived entirely in an open “band stand” cage for nine years with a lower mortality than in the rest of the monkey collection, which is permitted to go indoors some of the time. Occasionally one in poor health is frozen to death, and healthy ones may lose fingers, toes, or a part of the tail, but the general condition is so much improved that they present an attractive exhibit to visitors. Unless a storm be of great severity, wild animals are usually indifferent to it although they may seek their shelter. Snow apparently is no source of fear to them, and many enjoy playing in it. The general principles of the enclosure should be proper lighting, free access of air, dryness and shelter in time of storm, the last so arranged that the sleeping place is well protected. Appropriate