The possibility that the peculiar and distinctive disorders, acromegaly and acromegalic gigantism, were due to overactivity of the anterior lobe of the pituitary body has been suspected for many years. Although other data were not lacking to confirm the suggestion, it may be said that the possibility was first transformed into a probability by the production of gigantism in rats by injections of an emulsion of the anterior lobes of beef hypophyses by Evans and Long.1 Their prodigious animals could not actually be considered acromegalic, however. They underwent a general proportionate enlargement, but aside from a peculiar change in the ovaries they showed no qualitative structural alteration. The absence of the specific enlargement of the "acral parts," which gives the disease its name, might be attributed to the fact that in the rat the bony epiphyses never unite. It obviously became desirable to extend the experiment to larger animals