When you can spare the time,--and no time is wasted which is spent in getting a thorough and exhaustive knowledge of a serious case,--it is as good as a play to let even your hypochondriac patients, and those who are suffering chiefly from "nervous prosperity" in its most acute form, set forth their agonies and their afflictions in their fullest and most luxurious length, breadth, and thickness, watching meanwhile the come and go of the lines about the face-dials, the changes of the color, the sparkling and dulling of the eye, the droop or pain-cramp, or luxurious loll of each group of muscles, and quietly draw your own conclusions from it all. Many and many a time, in the full luxury of self-explanation, they will reveal to you a clew which will prove to be the master-key to your control of the situation, and their restoration to comfort, if not health, which you couldn't have got in a week of forceps-and-scalpel cross-examination. In only one class of patients is this valuable aid to knowledge absent, and that is in very young children; and yet, by what may at first sight seem like a paradox, they are, of all others, the easiest in whom to make not merely a provisional, but a final, diagnosis. They cannot yet talk with their tongues and their lips, but they speak a living language in every line, every curve, every tint of their tiny, translucent bodies, from their little pink toes to the soft spot on the top of their downy heads. Not only have they all the muscle-signs about the face-dial, of pain or of comfort, but, also, these are absolutely uncomplicated by any cross-currents of what their elders are pleased to term "thought." When a baby knits his brows he is not puzzling over his political chances or worrying about his immortal soul. He has got a pain somewhere in his little body. When his vocal organs emit sounds, whether the gurgle or coo of comfort, or the yell of dissatisfaction, they are just squeezed out of him by the pressure of his own internal sensations, and he is never talking just to hear himself talk. Further than this, his color is so exquisitely responsive to every breath of change in his interior mechanism, that watching his face is almost like observing a reaction in a test-tube, with its precipitate, or change of color. In addition, not only will he turn pale or flush, and his little muscles contract or relax, but so elastic are the tissues of his surface, and so abundant the mesh of blood-vessels just underneath, that, under the stroke of serious illness, he will literally shrivel like a green leaf picked from its stem, or wilt like a faded flower.