The tone of the vascular system is maintained by adrenalin. The nature of its influence upon muscles is not known, but probably the complete loss of muscular strength, which is one of the most noticeable symptoms of disease of the suprarenal capsules, is an indirect result of the lowering of blood-pressure. The muscles, it must be remembered, make up about one-third of the weight of the body of a muscular man. For the exchange of their waste products for food, they are dependent upon an efficient circulation. They are unable to display their normal vigour when the vascular system is not up to its work. =The Pituitary Body= is another ductless gland of dubious history. It is a round body, the size of a small marble, which occupies a deep recess in the floor of the skull, beneath the centre of the brain. It is composed of epithelial cells collected into irregular groups. No homologue of the pituitary body can be found in the invertebrate sub-kingdom. Its strange mode of development in vertebrate animals—it is present in them all, from fishes to mammals—and the mystery in which its prevertebral existence is hidden, provoke to speculation. We must be content to state that it is undoubtedly masquerading under an assumed name. “Pituitary body” is reminiscent of a long-abandoned theory that it secretes fluid into the upper chamber of the nose. Disease of the pituitary body is associated with a perversion of growth even stranger than that due to disease of the thyroid gland. The condition has been termed “acromegaly,” to indicate that all extremities—toes, fingers, nose, lips, tongue—undergo enlargement.