The balance of nature is an expression which is apt to be loosely invoked for all manner of purposes, but where wild life is concerned it is often used as an argument to prevent any alteration to an existing state of affairs. Man, however, in actual fact is ceaselessly upsetting the equilibrium of nature and almost every action of his upsets a natural balance, for instance, to mention but a few—developing agriculture, planting forests, cutting out forests, draining swamps, constructing dams and reservoirs, building great airfields or making new roads and railways. All this change is unavoidable and inevitable and no one can foresee the effect it is likely to have on the local wild life; sometimes the results are indeed remarkable. But the narrower interpretation of upsetting the balance of nature refers mainly to a situation in which there is for a variety of purposes the deliberate intent to alter the status of wild life, may be by the introduction of an exotic species, maybe by the elimination of a species already present. Such drastic changes can, though not necessarily, be fraught with considerable danger to the other species, and introductions into a favourable environment where natural enemies are absent or do not develop may result in the unimpeded and disastrous multiplication of the introduced species, such as the well-known examples of the rabbit in Australia, and the English sparrow in the U.S.A. So far my remarks have related to what can be termed an artificial alteration of nature's balance, oblivious of the fact that nature is not static and that nature itself is in a never-ceasing state of change. When I refer to nature not only do I mean the climate, the physical features, the forests, the vegetation and the wild life, but I include primitive man who always was and is, where he still occurs, part of nature. Primitive man filled his own little niche in the order of things, and with his primitive weapons and implements had little lasting effect on the zoological and botanical world around him.