IN all studies we are turning back to remoter and remoter causes, and to the investigation of origins; but, as we abstract and abstract, we are apt to get vaguer and vaguer, more and more are individual features merged in types, and in medicine we may find ourselves reduced at last to the emptiness of general counsels for a temperate and wholesome life. Nevertheless, the modern physician cannot be content with the knowledge that the patients under his care are victims of phthisis, of Bright's disease, of failing heart, of premature senile decay, and so forth, without a desire to learn the nature and direction of the processes by which such changes are initiated. As in but few instances he has discovered these small beginnings he is discontented; and it is well that he should be so. Our ancestors did not fail to see that diseases are moving things, so active that some demon or evil principle might be behind them; but this conception of activity, effective enough for instant purposes, contained no adequate notion of remote or latent causes. Some such notions may be traced in the ancient doctrines of the temperaments or diatheses, but were speculative and comparatively barren. Initial causes were, as we should expect, first observed and revealed in the infections, when a definite external pathogenic factor enters into a healthy or apparently healthy person; but even such events would seem to be very inconstant in their occurrence. Of two men exposed to such an attack, one would betray no sign of suffering, while the other would fall ill; an inconstancy indicating that the causation of an individual case of infection consists of far more than the intrusive element itself, which in some cases impinges upon a series of cooperating, in others of antagonistic causes. And if the patient succumbs, the outbreak of disorder is not immediate; a variable but specific interval elapses before its first manifestations. Now if from the recognised infections we turn to other diseases, we try to discover if some of these also arise from incidental agencies of a more occult kind, but having also their latent periods and gradual initiations. Others, again, may not be attributable to external elements, scarcely even as secondary and accelerating causes; but arise as later terms of processes implicit in the organism itself, perhaps even from the embryo.