SECTION I.—PHYSIOLOGY. 
THE PITUITARY BODY AND THE 
DIENCEPHALON 
ADDRESS BY 
PROF. P. T. HERRING, M.D., 
PRESIDENT OF THE SECTION. 
THE pituitary body, the ‘ Glans pituitam excipiens’ of Vesalius (1543), 
from the time of Galen to the seventeenth century, was looked upon as 
an organ for separating the waste products from the brain and diverting 
them into the nose and pharynx. In the transformation of vital into 
animal spirits the residues were removed as pituita or phlegm, and the act 
of sneezing was held in high esteem as a means of clarifying the mind. 
In 1660 Victor Schneider described the structure of the mucous membrane 
of the nose, and in 1672 Richard Lower finally disposed of the older 
theory. Lower indeed ventured to suggest that the pituitary secretes, 
not into the nose, but into the brain. 
The gland was termed the Hypophysis Cerebri by Soemmerring in 
1772, and Rathke, the embryologist, discovered its dual mode of origin 
in 1832. Clinical medicine gave the first clue to its function: the disease 
Acromegaly was described in 1886 by Pierre Marie, and somewhat later 
associated with overgrowth of the pituitary body. 
Experimental research upon the organ may be said to date from 1895, 
when Oliver and Schafer discovered that the gland contains an active 
principle, which, when injected into the blood, raises the blood pressure 
and increases the activity of the heart. In 1905 Alfred Frohlich described 
a pathological condition in man, associated with obesity and genital 
infantilism, to which he gave the name ‘ dystrophia adiposogenitalis.’ 
Since that time, and particularly during the last few years, great advances 
have been made in the knowledge of the functions of the pituitary body, 
and of that part of the brain to which it is attached. The work of Harvey 
Cushing calls for special mention, for to him and his pupils many of the 
most valuable contributions are due. 
ANATOMICAL AND STRUCTURAL FEATURES. 
The structures formed from the wall of the posterior part of the primary 
cerebral vesicle or diencephalon are perhaps more diverse in character 
than those of any other portion of the central nervous system. In 
addition to nerve cells and nerve tracts the diencephalon gives rise to 
organs obviously secretory, the choroid plexus, and, in fishes, the saccus 
vasculosus. ‘The paraphysis, when present, is probably glandular in 
function. Two prominent evaginations of the brain wall, one above and 
