In like manner, the pituitary body or hypophysis, which in man is a small organ about the size of a cherry, situated at the base of the brain, buried in the floor of the skull, and lying just behind the optic chiasma, was formerly rated as a rudimentary organ. It was, in fact, regarded as the vestigial remnant of a former connection between the neural and alimentary canals, reminiscent of the invertebrate stage. “The phylogenetic explanation of this organ generally accepted,” says Albert P. Mathews, “is that formerly the neural canal connected at this point with the alimentary canal. A probable and almost the only explanation of this, though an explanation almost universally rejected by zoölogists, is that of Gaskell, who has maintained that the vertebrate alimentary canal is a new structure, and that the old invertebrate canal is the present neural canal. The infundibulum, on this view, would correspond to the old invertebrate œsophagus, the ventricle of the thalamus to the invertebrate stomach, and the canal originally connected posteriorly with the anus. The anterior lobe of the pituitary body could then correspond to some glandular adjunct of the invertebrate canal, and the nervous part to a portion of the original circumœsophageal nervous ring of the invertebrates.” (“Physiological Chemistry,” 2nd ed., 1916, pp. 641, 642.) This elaborate piece of evolutionary contortion calls for no comment here. We are only interested in the fact that this wild and weird speculation was originally inspired by the false assumption that the hypophysis was a functionless organ. As a matter of fact, it is the source of two important hormones. The one generated in its anterior lobe is _tethelin_, a metabolic hormone, which promotes the growth of the body in general and of the bony tissue in particular. Hypertrophy and overfunction of this gland produces giantism, or acromegaly (enlargement of hands, feet, and skull), while atrophy and underfunction of the anterior lobe results in infantilism, acromikria (diminution of extremities, _i. e._ hands, feet, head), obesity, and genital dystrophy (_i. e._ suppression of secondary sexual characters). The posterior lobe of the pituitary body constitutes, with the _pars intermedia_, a second endocrine gland, which generates a stimulatory hormone called _pituitrin_. This hormone stimulates unstriated muscle to contract, and thereby regulates the discharge of secretions from various glands of the body, _e. g._ the mammary glands, bladder, etc. Hence the hypophysis, far from being a useless organ, is an indispensable one. Moreover, it is an integral and important part of the cryptorhetic system.