The liver in the mature animal, being the one destination of the blood
carried in the portal vein, necessarily becomes the recipient of all
medicinal and poisonous agents absorbed by the capillaries and venous
radicals of the stomach and intestines. This organ retains and lays up
for a time the heavier metals, such as the salts of copper and iron, the
iodides and bromides, the vegetable alkaloids such as nicotine, quinine,
morphia, and curare, the toxic elements of the bile, the ptomaines and
toxins produced by gastric and intestinal fermentations, indol, phenol,
etc. Some agents it transforms, as peptones (which it renders
non-poisonous), casein, the carbonate of ammonia and its salts with
vegetable acids, also indol and phenol, which it combines with sulphuric
acid as indyxol and phenyl sulphate, thus rendering them much less
toxic. The destructions or new combinations established in the cases of
the ptomaines and toxins may explain why such agents are usually much
less poisonous when taken by the stomach than when generated in tissues
or blood, or when injected hypodermically. Another interesting fact in
connection with the ingestion of these bacteridian products (ptomaines
and albumoses) is that, when the liver functions are normal as evidenced
by the production of glycogen, the toxins are largely destroyed, and
they fail to produce poisoning, whereas with a functionally deranged
liver and no production of glycogen, they retain their potency, almost
as if injected subcutem.