Experiments have been recently made by Mr. Sanson with a view to
settling the question whether oats have or have not the excitant
property that has been attributed to them. The nervous and muscular
excitability of horses was carefully observed with the aid of graduated
electrical apparatus before and after they had eaten a given quantity
of oats, or received a little of a certain principle which Mr. Sanson
succeeded in isolating from oats. The chief results of the inquiry are
as follows: The pericarp of the fruit of oats contains a substance
soluble in alcohol and capable of exciting the motor cells of the
nervous system. This substance is not (as some have thought) vanilline
or the odorous principle of vanilla, nor at all like it. It is a
nitrogenized matter which seems to belong to the group of alkaloids; is
uncrystallizable, finely granular, and brown in mass. The author calls
it "avenine." All varieties of cultivated oats seem to elaborate it, but
they do so in very different degrees. The elaborated substance is the
same in all varieties. The differences in quantity depend not only on
the variety of the plant but also on the place of cultivation. Oats of
the white variety have much less than those of the dark, but for some
of the former, in Sweden, the difference is small; while for others, in
Russia, it is considerable. Less than 0.9 of the excitant principle per
cent. of air-dried oats, the dose is insufficient to certainly affect
the excitability of horses, but above this proportion the excitant
action is certain. While some light-colored oats certainly have
considerable excitant power, some dark oats have little. Determination
of the amount of the principle present is the only sure basis of
appreciation, though (as already stated) white oats are likely to
be less exciting than dark. Crushing or grinding the grain weakens
considerably the excitant property, probably by altering the substance
to which it is due; the excitant action is more prompt, but much less
strong and durable. The action, which is immediate and more intense
with the isolated principle, does not appear for some minutes after the
eating of oats; in both cases it increases to a certain point, then
diminishes and disappears. The total duration of the effect is stated to
be an hour per kilogramme of oats ingested.
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