The behaviorism of the autocoids is more obscure. They become conspicuous chiefly by their absence. Thus the removal of the parathyroids (part of the thyroid apparatus situated on either side of the larynx and windpipe) produces convulsions. Its autocoid is therefore believed to be of a restraining type. The removal of the thyroids themselves produces cretinism, and thyroxin, their active principle (it is sixty percent iodine) was isolated only recently by E. C. Kendall, of the Mayo Foundation. Suprarenal extract (from the suprarenal apparatus near the kidneys) aids in recovery from fatigue. As to the pituitary apparatus at the base of the brain, “gigantism is supposed to be due to an overactive anterior lobe; obesity and sexual infantilism to the lack of secretion of the posterior lobe.” (Watson.) The thymus gland (in the neck near the thyroids) is believed by Dr. Walter Timme to be linked with the pineal (which is a part of the brain structure) in a related system dominating the life cycle from birth to puberty. If the function of the pineal is disturbed in children, “there is a rapid development of the reproductive organs, precocity, and an increased growth of skeleton. It is thus supposed that this gland furnishes an inhibitory autocoid.” (Watson.) To the absence of the puberty gland (also called the interstitial, and endocrine not to be confounded with the gonads, or true sex cells, to which is entrusted the reproductive function)--to the absence of the puberty gland is attributed the observed effects of castration, and “there is a growing tendency on the part of investigators ... to believe that man is as old as his glands.” Therefore, “since the remaining glands apparently cannot stay youthful in the absence of a sufficient output from the puberty glands, it is only natural to connect senescence or old age with the decline in the output from this gland.” (Watson.) Hence all the experiments in rejuvenation, the transplantation of glands from monkeys and goats, made from the days of Brown-Sequard (famous about the year 1889) down to those made by Steinach, Voronoff and many others of the present time. Thus the simian becomes our “glandcestor,” so to speak, whether he be our forbear or not. But let us take leave of all this physiology and observe what sort of psychology we can get from our receptors, conductors and effectors under experimental conditions.