Dr. Ritchie has supplied a fascinating study in faunal evolution in "The Influence of Man on Animal Life in Scotland." I know of no better exposition of the need for sensible and well-considered protection than is supplied by this book.
Dr. Ritchie divides his subject into two parts—deliberate and indirect interference with animal life. In the first he groups domestication, intentional destruction of animals for various reasons, protection of animals for other reasons, and the introduction of new forms. In the second he deals with changes in natural environment and the influence on animals, cultivation, civilisation, and the accidental or unintentional introduction of creatures for the most part classed as pests. An entirely different method of grouping or analysis of results would be the dividing of those from which man derives benefit from those which are detrimental to his welfare. Deliberately or unintentionally man has in his dealings with animals derived profit and loss, and he has by no means invariably succeeded in attaining the ends that he desired, or which, at first blush, seemed likely to result. Animals, consciously or unconsciously, treat man as a competing species, and, however warmly a Krapotkin may advocate mutual aid, or a Drummond urge the harmony of nature, the painful fact remains, man and the primitive protozoan alike strive and have to strive to exist at all.
So long as the disturbance of nature is confined to cultivation of land or domestication of useful animals, necessities for man's existence, this disturbance is not only justifiable, but a duty. It may mean, it is certain to mean, destruction of many existing forms as well as individuals, but the loss cannot be helped; it is true, however, that in few cases has the cultivation for food or the destruction of animals for the same reason been the cause of extinction; it is when commercialism demands
