30 PRESIDENT’S ADDRESS. 
the condition has been termed ‘ acromegaly’ (enlargement of extre- 
mities). The association of this condition with affections of the 
pituitary was pointed out in 1885 by a distinguished French physician, 
Dr. Pierre Marie. Both ‘ giants’ and ‘ acromegalists’ are almost 
invariably found to have an enlarged pituitary. The enlargement 
is generally confined to one part—the anterior lobe—and we conclude 
that this produces hormones which stimulate the growth of the body 
generally and of the skeleton in particular. The remainder of the 
pituitary is different in structure from the anterior lobe and has a 
different function. From it hormones can be extracted which, like 
those of the suprarenal capsule, although not exactly in the same 
manner, influence the contraction of the heart and arteries. Its 
extracts are also instrumental in promoting the secretion of certain 
glands. When injected into the blood they cause a free secretion of 
water from the kidneys and of milk from the mammary glands, neither 
of which organs are directly influenced (as most other glands are) 
through the nervous system. Doubtless under natural conditions 
these organs are stimulated to activity by hormones which are pro- 
duced in the pituitary and which pass from this into the blood. 
The internally secreting glands which have been mentioned (thyroid, 
parathyroid, suprarenal, pituitary) have, so far as is known, no other 
function than that of producing chemical substances of this character 
for the influencing of other organs, to which they are conveyed by 
the blood. It is interesting to observe that these glands are all of very 
small size, none being larger than a walnut, and some—the parathy- 
roids—almost microscopic. In spite of this, they are essential to the 
proper maintenance of the life of the body, and the total removal of 
any of them by disease or operation is in most cases speedily fatal. 
There are, however, organs in the body yielding internal secretions 
to the blood in the shape of hormones, but exercising at the same time 
other functions. A striking instance is furnished by the 
pancreas, the secretion of which is the most important of 
the digestive juices. This—the pancreatic juice—forms the external 
secretion of the gland, and is poured into the intestine, where its action 
upon the food as it passes out from the stomach has long been recog- 
nised. It was, however, discovered in 1889 by von Mering and Min- 
kowski that the pancreas also furnishes an internal secretion, containing 
a hormone which is passed from the pancreas into the blood, by which 
it is carried first to the liver and afterwards to the body generally. This 
hormone is essential to the proper utilisation of carbohydrates in the 
organism. It is well known that the carbohydrates of the food are con- 
verted into grape sugar and circulate in this form in the blood, which 
always contains a certain amount; the blood conveys it to all the cells of 
the body, and they utilise it as fuel. If, owing to disease of the pan- 
Pancreas. 
