This section is from the book "A Text-Book Of Pharmacology, Therapeutics And Materia Medica", by T. Lauder Brunton. Also available from Amazon: A text-book of pharmacology, therapeutics and materia medica.
The pancreatic juice is important in the process of digestion, as it has the threefold power of converting starch into sugar, of digesting proteids with the formation of peptones, and of splitting up and emulsifying fats.
The process of secretion in the pancreas is associated with increased blood-supply as in other glands. Its nerves arise from the hepatic, splenic, and superior mesentery plexuses, with branches from the vagi and splanchnics. Electrical stimulation of the gland itself will cause secretion, and so will stimulation of the medulla oblongata. It is arrested by powerful irritation of sensory nerves, such as the central end of the vagus, the crural, or sciatic, and by the production of nausea or vomiting.
When fibrin is digested with pancreatic juice the solution soon begins to swarm with bacteria, and products of decomposition occur, among which is indol with a peculiarly disagreeable odour.
When calomel is added to pancreatic juice, it does not impair its digestive action upon starch, proteids, or fats, but it arrests decomposition, and thus prevents the formation of indol and scatol, although leucin and tyrosin, which are normal products of pancreatic digestion, are still formed. Salicylic acid has a similar action.1
After the administration of calomel the stools are often of a green colour, and this is due to unaltered bile. From the experiments on biliary fistulae already mentioned it is probable that this bile in the motions is not due to increased secretion by the liver, but to the occurrence of diminished absorption, caused by its more rapid passage through the intestine, and possibly also to lessened transformation from the effect of the calomel in preventing its decomposition.