Annual Address by the President. 
9 
acute inflammation of the gland with necrosis, where VateFs ampulla 
is blocked by a biliary calculus. 
And, curiously enough, the products of digestion, particularly the 
peptones, are themselves of a poisonous nature, producing symptoms 
of an extremely, toxic nature, if they are injected into the blood. For- 
tunately, under . normal conditions, they are changed into innocuous 
compounds by hepatic metabolism. 
The liver probably holds the highest place as an organ peculiarly 
adapted to defend the system from the entrance of hurtful products. 
Its functions are twofold, (1) metabolic and (2) toxicidal. The 
proper performance of both functions is absolutely necessary, and, 
although the metabolic function is the primary and more essential, 
still it is safe to say that if the toxicidal powers were annulled even 
temporarily, an extremely dangerous state would ensue, because all the 
toxin, both living (bacteria) and dead (ptomaines), which during health 
passes along the portal system of veins from the alimentary canal to 
the liver, where it is rendered harmless by the activity of the liver 
cells, would, under the altered conditions, pass directly into the sys- 
temic circulation. 
Turning now our attention to the chemical characteristics of the 
secreting glands, w T e find that recent discoveries have revealed processes 
of such minute complexity as to excite wonder at the marvelous smooth- 
ness of the machinery. I refer to the “hormones,” or the chemical 
messengers, which are carried by the blood stream to various glands 
in which they excite specific secretion. Many of these are known, but 
probably, the most important is that responsible for the secretion of 
trypsinogen by the pancreas. This subject has been extensively studied 
by Starling, and the following short description will suffice. It is found 
that the active cells of the duodenum and small intestine manufacture 
a specific substance called “prosecretin.” This is transformed by the 
action of the acid chyme into a substance called “secretin,” which, being 
taken up by the blood stream, passes to the pancreas, where it exercises 
a specific effect, producing a free flow of pancreatic juice containing 
trypsinogen. Trypsinogen is never secreted without the presence . of 
secretin in the blood circulating through the pancreas; and the injec- 
tion of secretin into the blood of an animal will, in a very short time, 
cause a free flow of pancreatic juice containing trypsinogen, whether the 
duodenum contains chyle or is empty. As soon as the pancreatic juice 
reaches the small intestine the contained trypsinogen causes the flow of 
a ferment called “enterkinase,” which again reacts on the trypsinogen, 
producing trypsin, which possesses the power of turning proteids into 
peptones. 
In addition to the production of enterkinase, an alkali is poured out 
