150 SECTIONAL ADDRESSES 
of other glands upon which they act. ‘The secondary results may indeed 
be more pronounced than the primary. 
The mode of action of the active principles of the posterior lobe is 
even more obscure. It has already been noted that effects of a different 
nature are produced according to the way in which the extracts are 
exhibited. We cannot at present be certain whether they act locally 
upon the diencephalon, or more generally through the blood stream. 
Possibly both methods may be utilised. 
In disturbances of the human pituitary body, and especially in those 
occasioned by the growth of adenomata, there is the further complication, 
stressed by Harvey Cushing, that the pituitary body lies in a rigidly 
enclosed case. The growth of one element must be at the expense of 
another. An adenoma of the growth-producing cells not only exercises 
its own action by increasing production of the growth hormone, but it 
leads to a diminishing output of other hormones, the lack of which shows 
its own train of symptoms. Hence arise so many of the different syn- 
dromes associated with pituitary disturbance. Secondary effects still 
further complicate the picture. ‘The hypothalamus may be involved, and 
differences of opinion arise as to whether symptoms are attributable to the 
pituitary or to the brain. 
THe ANTERIOR LOBE. 
Hormones have been more or less completely separated from the anterior 
lobe which stimulate growth and exercise a-controlling influence over 
many important organs of the body, the gonads, thyroids, parathyroids, 
thymus, cortex of the suprarenals and the mammary glands. Extracts 
have also been prepared which exert a powerful influence upon meta- 
bolism, especially of carbohydrate and fat. 
The growth hormone has been so far isolated by Evans to yield a 
white hygroscopic powder, stable in dry air, and containing about 15 per 
cent. of nitrogen. From Cushing’s observations in adenomata it is 
probably a product of the acidophil cells. The growth hormone has 
been successfully used to produce giants in growing rats and dogs. 
It has also induced conditions in adult dogs similar to acromegaly. The 
hormone appears to stimulate the osteoblast to increased bone formation. 
It would be interesting to test its effects in cartilaginous fishes, the 
pituitaries of which are lacking in acidophil cells. Impure extracts bring 
about splanchnomegaly and other changes which may be due to their 
admixture with other active principles. 
The gonad-stimulating, or gonadotropic hormone, is probably a 
product of the basophil cells. In a basophil adenoma recorded by Teel 
typical hypertropic changes occurred in the ovary. Zondek and Aschheim, 
and Smith and Engle, found that implantation of anterior lobe tissue in im- 
mature female rats and mice brings about rapid sexual maturity. Zondek 
and Aschheim prepared two extracts of the anterior lobe, which they called 
prolan A and prolan B, the one acting as a stimulus to the maturation of 
the Graafian follicle, and the other bringing about its rapid luteinisation. 
Collip has shown that the material of these authors, prolan, is obtained 
from the placenta and from the urine of the pregnant animal. Evans and 
