Poison-ivy has a
distressing toxic action on the skin of people who become sensitized to it. The
offending substance of the plant is an oil which is present throughout root,
stem, leaf, flower, and fruit. Tearing or bruising of any part liberates the
oil that may come in contact with the exposed parts of the body, either
directly or by handling contaminated objects.
This oil may stick
to clothing, especially boots, tools, or picnic baskets, and may be easily
transferred to the hands and the face and by touching, rubbing or handclasp, to
other persons who have not been directly exposed at all.
Pets can also
become contaminated by running through patches of poison-ivy. Although animals
do not react to the poison, a sensitive person can be poisoned merely by
petting a contaminated animal. The oil is also said to be vaporized by heat
such as would be present in a bonfire or a smudge. The vapour thus formed may
be carried by the smoke and if a susceptible person walks through the smoke or
inhales it, very serious reactions may result. The oil may also be vaporized,
or sprayed out like an atomizer, from fresh plants as they are being cut and
contaminate a nearby person or the person's clothing even though there is no
direct contact with the poison-ivy plant.
greatly in susceptibility to ivy poisoning and many have never suffered any ill
effects. However, those in the latter category should not take for granted that
they are immune for all time.