THE MORPHOLOGY OF PARS INTERMEDIA OF THE HUMAN HYPOPHYSIS*

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Abstract
The general features of the pars intermedia from late fetal stages to the adult are described and illustrated. Quantitative data on record on its relative size in animals and man indicate that it is 2-10 times as large in animals as in man. Original data are submitted on the absolute and relative wt. of the epithelial portion and the colloid in 111 normal o" human adults. These show that the epithelium averages 0.9% of the whole hypophysis or 1.1% of the total epithelium of the gland. The absolute wt. averages 4.6 mgm., which is about 2 X as much as in the newborn, but varies from 0.5 mgm. to 20.1 mgm. The small amount of tissue it may represent in apparently healthy individuals is emphasized. It increases slightly with age. The amount of colloid averages slightly more than the epithelium, and is even more variable. There is no correlation between the amount of colloid and the'' amount of epithelium. There is no significant correlation between stature and pars intermedia. Curves of wt. distribution, coefficient of variation and other statistical constants are recorded.