Investigations have also been conducted with the various known
constituents of this "coffee oil." Erdmann[254] found that in doses of
between 0.5 and 0.6 gram per kilo of body weight, furane-alcohol kills a
rabbit by respiratory paralysis; and that the symptoms of poisoning are
a short primary excitement, salivation, diarrhea, respiratory
depression, continuous fall of the body temperature, and death from
collapse with respiratory failure. In man, doses of from 0.6 to 1 gram
of furane-alcohol increased respiratory activity without producing other
symptoms.

However, man is not as susceptible to these compounds as are the smaller
animals. But even if their relative susceptibility be assumed to be the
same, the lethal dose given the rabbit is equivalent to giving a
140-pound man one dose containing the furane-alcohol content of over
5,000 cups of coffee. Thus, in view of the very apparent minuteness of
the quantity of this compound present in one cup of coffee, together
with the fact that it is not cumulative in its physiological action, the
importance of its toxic properties becomes very inconsequential to even
the most profuse and inveterate coffee drinkers.

Burmann[255] reported the volatile principle to have a reducing action
on the hemoglobin; a depressing effect on the blood pressure; a
depressant action on the central nervous system, disturbing the cardiac
rhythm; and an action on the respiratory centers, causing dyspnea. The
report of Sayre[256] regarding the minimum lethal dose of the
concentrated combined active principles of coffee obtained from dry
distillation is, for frogs, administered intraperitoneally and
subcutaneously, 0.03 cubic centimeters per gram of body weight; for
guinea pigs per stomach, 7.0 cc. per kilogram of body weight, and
administered intravenously and intraperitoneally, about 1.0 cc. per
kilogram.

This evidence regarding the physiological action of caffeol can not in
any wise be construed to indicate a harmfulness of coffee. The
percentage of these volatile substances in a cup of coffee infusion is
so low as to be relatively negligible in its action. And, again, the
caffein content of the brew, as will be seen, tends to counteract any
possible desultory effects of the caffeol.

_General Physiological Action of Caffein_

More attention has been given to the study of the physiological action
of caffein than to that of the other individual constituents of coffee.
Since certain of th