148 SECTIONAL ADDRESSES 
hour’s time. Zondek speaks of the pituitary sex hormone as the motor 
which sets the reproductive cycle going, and Harvey Cushing adds the 
comment that the emotional self-starter is probably in the diencephalon. 
The hypothalamus, comprising the tuber cinereum, mammillary 
bodies, infundibulum and pars nervosa of the pituitary body, optic 
chiasma and subthalamic tectal region, forms an important part of the 
diencephalon which has been slow to reveal its secrets. The region is 
difficult of access for experimental purposes, and its exposure is attended 
by damage which may obscure the results obtained. Moreover, both 
Harvey Cushing and Beattie have shown that some anesthetics prevent 
the occurrence of reactions which might otherwise be expected to result 
from stimulation of its parts. Much information has been obtained 
from the clinical examination of patients suffering from lesions of the 
hypothalamus, but the mass of information thus yielded is extremely 
difficult to interpret... Harvey Cushing has demonstrated in the conscious 
human being an immediate and striking response to perfusion of the 
third ventricle by solutions of pituitrin and of pilocarpine. The response 
was so rapid that the drugs could not have been absorbed into the blood 
vessels, but must have acted locally, a fact which strongly suggests the 
presence in some part of the third ventricle of a receptor mechanism. 
The effects were those of a general vaso-dilatation of the skin blood 
vessels, profuse sweating and a fall in blood pressure. The patient’s 
temperature fell, as did also the basal metabolic rate, both remaining low 
for some time. The same dose of pituitrin given intravenously to the 
same patient had the opposite effect upon the circulation, producing pallor 
with no sweating, and increased intestinal peristalsis. Injected sub- 
cutaneously the dose had no appreciable effect except as an antidiuretic. 
Perfusion of pituitrin through the ventricles of dogs gave rise to vascular 
dilatation, salivation, excessive panting, pulmonary cedema and gastro- 
intestinal hypertonicity, results which were prevented by a previous use 
of atropine. 
Harvey Cushing assumes as a working hypothesis that, under emotional 
stimuli, the posterior lobe of the pituitary body discharges its secretion 
into the cerebrospinal fluid, or by the venous portal system into the 
hypothalamus, where it diffuses through the ependyma and influences 
nuclei in this part of the brain to bring about a parasympathetic effect. 
‘ Beattie and his co-workers have obtained somewhat similar results 
from the direct stimulation of various parts of the hypothalamus in animals, 
and they support Cushing’s hypothesis of the presence of a parasympathetic 
centre in the hypothalamus. . They found that stimulation of the lateral 
margin of the infundibulum gives rise to increased peristalsis and secretion 
in the stomach, which disappears on section of the vagus. There is also 
increased tone and movement in the bladder. Stimulation of the tuber 
cinereum produces slowing of the heart and other cardiac effects revealed 
by the electrocardiograph. 
Evidence has been accumulating that there is also an important sym- 
pathetic mechanism in the hypothalamus. Claude Bernard in 1849 dis- 
covered that puncture of the wall of the fourth ventricle produces a 
glycosuria. Harvey Cushing and his pupils have shown that in dogs a 
