Very soon after the report of Von Hochwart's prodigy appeared, an experimental research on the pineal was begun in New York. The pineal glands of a number of young bullocks were obtained and used for feeding, to see whether an overaction of the internal secretion could be produced. Guinea pigs, kittens and rabbits were used. The experiments covered about two years in time. Of a dozen small kittens, the subjects outgrew the controls rapidly in activity, size, intelligence, and resistance to intercurrent disease. Of ten small rabbits, the controls weighed about a third less than the subjects, which were strikingly clean, active, fat and salacious. Feeding of the gland was then extended to a particular class of defective children, children with well-shaped heads, normal eyes, symmetrically functioning limbs, excellent digestion, strong muscles and generally, normal, sometimes rapid growth. It is to them, particularly when mental normality has progressed up to the eighth, tenth or twelfth year and stopped, that the term "moron" has been applied. They have been a hopeless lot, belonging to the limbo of the incurables. Moreover, they, emphatically the physically normal ones, differ from one another enormously in the extent to which mental operations are possible. As all transitions and degrees exist, no definite classification and subdivision of them has been made. Yet ever since the cretin, once looked upon as an eternally damned defective, was transformed by thyroid feeding into an apparently normal being, there has been no dearth of effort to find the right kind of internal secretion to fit their desperate situations, but in vain. In defectives with definitely, organically damaged brains, no result of course was to be expected. In those of any class over fifteen, no response has been elicited by feeding pineal gland. In the others the results have been contradictory. A set of observations have related the pineal to muscle function, inviting comparison of it with the thymus. There is a singular muscle shrinking and deforming disease, known as progressive muscular dystrophy, hitherto a complete and unsolved mystery. Newer studies of the pineal in this disease during life by means of the X-ray have shown it calcified, that is, buried in lime salts, which signifies put out of business. Recently thus another hint as to its function has been ferreted out. The tadpole as a reagent to test out the growth effects of different glands of internal secretion has also been employed for the pineal. Ten-day-old tadpoles fed on pineal present a marked translucency of the skin due to a retraction of the skin pigment cells. Now without a doubt a number of as yet unknown growth and metabolic effects follow exposure of the body to the complete gamut of light rays. The interesting suggestion follows that the pineal influences the body by varying the degree of light ray reaction.