The easiest division of every whole is into two halves. Thus day and night are bisected by noon and midnight, the year by both the solstice and the equinox; the racer turns in the middle of his course; curricula, apprenticeships, and long tasks have, from immemorial time, celebrated the completion of their first moiety, and halfway houses divide established courses of travel. So, too, we speak of middle age and think vaguely of it as half way between birth and death or between adolescence and senescence. If we think of life as a binomial curve rising from a base line at birth and sinking into it at death, midway is the highest point with the longest ordinate; and as the crest of a wave has its spindrift, so life at this point often foams, or at least shows emulsive tendencies. We come in sight of the descent while the ascent behind is still visible. The man of thirty-five hopes to live the allotted span of seventy and at forty he knows that in another two-score years his work will cease; and thus some comparison of the past and future is inevitable. Some begin taking stock of what has been and what remains to be done, reckoning only from the date of entering upon their careers and trying thus to judge its future by its past. Thus sooner or later there comes to all a realization that the tide that “drew us from out the boundless deep” begins to “turn again home.” These meridional perturbations usually come earlier in women than in men, and this has been called their “dangerous age.” Both sexes realize that they face the bankruptcy of some of their youthful hopes, and certain temperaments make a desperate, now-or-never effort to realize their extravagant expectations and are thus led to excesses of many kinds; while others capitulate to fate, lose heart, and perhaps even lose the will-to-live. Osler was the evil genius, the croaking Poe raven of this period. If such pronouncements as his stimulate talent, which is longer lived, they depress genius, which blossoms earlier. On the height of life we ought to pause, circumspect, turn from the dead reckonings of the start, and ascend as into an outlook tower to see, before it is too late, if we need to reorient our course by the eternal stars. Here we begin the home stretch toward the finish. Change, or at least thoughts of change, arise even in those most successful, as biography so abundantly shows, while even partial failure impels many to seek new environments and perhaps callings and some are driven to mad new ventures. Most, however, despite a certain perturbation, go on perhaps a score of years, and instead of anticipating old age wait till it is upon them and they have to restrict their activities or retire; then only do they accept the burden of years. The modifications in the _vita sexualis_ which middle life brings are only now beginning to be understood in their true significance. Its first flush has come and gone and some settle to the tranquil fruition of a happy married life,