154 SECTIONAL ADDRESSES 
fibres which convey secretory impulses to the gland. Removal of the 
posterior lobe in dogs does not always produce polyuria, and this is ex- 
plained by Trendelenberg as due to the presence of the hormone in the 
floor of the third ventricle. That this is a possible factor will be apparent 
from the frequency with which cells of the pars intermedia are normally 
found in this part of the brain wall. Further evidence of the importance 
of the pituitary in the control of water metabolism is seen in the experi- 
ments by Brill. The kidney vessels of a dog were perfused alternately 
with blood from a normal dog and blood from a dog which had had its 
pituitary body removed. Polyuria and retention of chlorides were 
obtained with the blood from the animal lacking a pituitary body. 
Cushing expresses the view that grey matter in the hypothalamus, 
possibly the nucleus supraopticus, is an important cell station for the 
integration of nerve impulses regulating water intake and output, and 
that the hypothalamus and the posterior lobe of the pituitary body make 
up a neuro-epithelial structure, the parts of which are mutually inter- 
dependent in their functions. 
The relationship of the secretion of the posterior lobe to the metabolism 
of carbohydrate and of fat is still obscure. Goetsch, Cushing and 
Jacobson obtained evidence of an influence of the posterior lobe upon 
carbohydrate metabolism, and looked to the reflex liberation of a pituitary 
hormone as the cause of glycogenesis in the liver. Burn showed that an 
extract of the posterior lobe, which he later identitied in the vasopressin 
fraction, prevents the fall of blood sugar which follows an injection of 
insulin. Vasopressin has little immediate action upon the amount of 
sugar in the blood, and Dale regarded the pituitary principle as a direct 
antagonist to insulin. Hynd and Rotter found that in white rats, 
especially in those upon a carbohydrate diet, vasopressin induces a slight 
hyperglycemia accompanied by a fall in liver glycogen and a rise in 
muscle glycogen. The amount of fat in the liver increases, as was first 
pointed out by Coope and Chamberlain, but soon falls and is followed 
by a greater accumulation of glycogen. The ultimate effect of the in- 
jection is the reverse of that first seen. Raab ascertained that pituitrin 
decreases the amount of fat in the blood, and is the more potent when 
injected into the ventricle. Moreover the effect is abolished by a variety 
of nerve lesions. On these grounds Raab believed that pituitrin acts on 
a nervous mechanism in the hypothalamus. In later work Raab con- 
cluded that a separate principle is the factor responsible, and that it is 
a product of the anterior lobe. 
Smith has shown that injuries to the tuber cinereum may result in great 
obesity in rats, and Cushing has reported that one of Maddock’s dogs, 
in which a clip was placed on the pituitary stalk, eventually became very 
fat. 
The deposition of fat in various parts of the body and the increased 
tolerance for sugar are well-known features of some forms of pituitary 
disturbance in man, but the opposite conditions also occur. It is at 
present impossible to determine how far the posterior lobe of the pituitary 
is concerned in these alterations of metabolism. Many of the observations 
were made before the importance of the anterior lobe was discovered. 
