We must regard it as a clinical fact that the thyroid reduces pressure. The original experiments of Oliver and Schäfer seem conclusive. Brunton said: “Thyroid gland, when taken by the mouth, dilates the peripheral vessels, making the skin warm and moist, and quickens the pulse. In this respect it antagonizes the suprarenal secretion. Besides this effect on blood pressure, it has other effects on metabolism which are important.” Biedl says: “If thyroid or iodothyrin be given continuously for two or three weeks, the amount of CO-excretion will be increased by 15 to 16 per cent. The nitrogenous interchanges are invariably disturbed by thyroid; the increased decomposition of albumen is expressed by an increased excretion of nitrogen. Thyroidism also brings about a considerable increase in the amount of calcium excreted in the fæces, the calcium carrying off with it a large proportion of phosphorus.” This phosphorus loss may explain some of the feeling of weakness and exhaustion that thyroid feeding often causes; this a good phosphate food such as Bynogen will help to remove. It is thus evident that we have in thyroid medication something much more than a mere tension depressor. Its other properties, influencing excretion, explain to some extent its sphere of usefulness and its drawbacks. The increased excretion of calcium may be very beneficial in atheroma, but is probably not an advantage in other ways. An observant man, who did not need it, was taking thyroid rather freely; he cut his finger and could not get it to heal. Thinking that this might be the result of calcium loss, he stopped the thyroid, and his wound healed, as he said, in a few hours. To the increased general metabolism that thyroid produces is due its striking effects in myxœdema: the new tissues, abnormal in quantity if not in essence, are absorbed, and the face and limbs resume their natural appearance. Senility and myxœdema are so closely related that one would naturally expect the same results to ensue. A fair steady trial will prove that such is the case, but all such clinical experiments need to be carried out in each individual case with thoroughness, faith and intelligent observation. Failure may at first be the verdict, but it is in most cases due to some defect in method. A thoughtful review of our physiological knowledge of endocrine actions will often show where lies the fault. A carping critic may say, What is your physiological knowledge of the action of these glands? And one must humbly answer, Not very much. But we are going to find our way through the twilight of our ignorance, partly by physiological experiment, but chiefly by clinical results. We must also be encouraged by the thought that all these clinical trials are without risk. What matters it if we produce temporary symptoms of hyperthyroidism? We can always correct them or retrace our steps. Russell Lowell’s proverb was, “A man who never makes a mistake never makes anything.” In such