There is perhaps no more fascinating story in the history of science than that of the discovery of these so-called ductless glands. Part of its special interest is due to the fact that clinicians, surgeons, experimental physiologists, pathologists and chemists have all combined in splendid teamwork to win the victory. No such miracles have ever before been wrought by physicians as those which we see in connection with the internal secretion of the thyroid gland. The myth of bringing the dead back to life has been associated with the names of many great healers since the incident of Empedocles and Pantheia, but nowadays the dead in mind and the deformed in body may be restored by the touch of the magic wand of science. The study of the interaction of these internal secretions, their influence upon development, upon mental process and upon disorders of metabolism is likely to prove in the future of a benefit scarcely less remarkable than that which we have traced in the infectious diseases. CHEMISTRY IT is not making too strong a statement to say that the chemistry and chemical physics of the nineteenth century have revolutionized the world. It is difficult to realize that Liebig's famous Giessen laboratory, the first to be opened to students for practical study, was founded in the year 1825. Boyle, Cavendish, Priestley, Lavoisier, Black, Dalton and others had laid a broad foundation, and Young, Frauenhofer, Rumford, Davy, Joule, Faraday, Clerk-Maxwell, Helmholtz and others built upon that and gave us the new physics and made possible our age of electricity. New technique and new methods have given a powerful stimulus to the study of the chemical changes that take place in the body, which, only a few years ago, were matters largely of speculation. "Now," in the words of Professor Lee, "we recognize that, with its living and its non-living substances inextricably intermingled, the body constitutes an intensive chemical laboratory in which there is ever occurring a vast congeries of chemical reactions; both constructive and destructive processes go on; new protoplasm takes the place of old. We can analyze the income of the body and we can analyze its output, and from these data we can learn much concerning the body's chemistry. A great improvement in the method of such work has recently been secured by the device of inclosing the person who is the subject of the experiment in a respiration calorimeter. This is an air-tight chamber, artificially supplied with a constant stream of pure air, and from which the expired air, laden with the products of respiration, is withdrawn for purposes of analysis. The subject may remain in the chamber for days, the composition of all food and all excrete being determined, and all heat that is given off being measured. Favorable conditions are thus established for an exact study of many problems of nutrition. The difficulties increase when we attempt to trace the successive steps in