sunken; the eyes have fallen far back; the lips are drawn in. All of these changes indicate to us, when we think upon them, the fact that there has been a certain shrinkage and shrivelling of that which is within and beneath the skin. Expressed in technical terms, we should call this an atrophy, and to anatomists the mere sight of the face of a very old person reveals at once this fundamental fact of an atrophy of the parts, an actual loss of some of their bulk, which is one of the most characteristic and fundamental marks of old age. The gait becomes shuffling, the foot is no longer lifted free from the ground, as the old man walks along. He does not rise upon his toes, but the sole of the foot is kept nearly flat and as he drags it cumbrously forward it is apt to strike upon the sidewalk. This indicates to the physiologist a lessened power in the muscles, a lessened control over the action of these muscles, an inferior coordination of the movements, so that there has been in the old man, judged by his gait alone, a physiological deterioration as well as an anatomical atrophy. You notice too his slow speech, often difficult hearing, and imperfect sight. All of these qualities show a loss, and we commonly think of the old as those who have lost most, who have passed beyond the maximum of development and are now upon the path of decline, going down ever more rapidly. One of the chief objects at which I shall aim in this course of lectures will be to explain to you that that notion is erroneous, and that the period of old age, so far from being the period of true decline, is in reality essentially the period in which the actual decline going on in each of us will be least. Old age is the period of slowest decline—a strange, paradoxical statement, but one which I hope to justify fully by the facts I shall present to you in this course. In the old person you note that there is in the mind some failure and also loss of memory—less mental activity, greater difficulty in grasping new thoughts, assimilating new ideas, and in adapting himself to unaccustomed situations. All this betokens again the characteristic loss of the old. And as we turn now from these outward investigations to those which the anatomist opens up to us, we learn that in the interior of the body, and in every organ thereof, the species of change which I have referred to as characteristic of the very old, is going on and has become in each part well marked. Let us first examine the skeleton. In youth many parts of the skeleton are soft and flexible, like the gristles and cartilages, which join the ribs to the breastbone, but in the old man they are replaced by bone. Bone represents an advance in organization, in structure, as we say, over the cartilage. The old man has in that respect progressed beyond the youthful stage; but that progress represents not a favorable change; the alteration in structure from elastic cartilage to rigid bone is physiologically disadvantageous, so that though the man has progressed in the organization or anatomy of his body, he has really
