Poison
It is not generally known that the much-admired laburnum contains a
strong poison, and is therefore an exceedingly dangerous plant. All its
parts--blossoms, leaves, seeds, even the bark and the roots--are charged
with a poison named cytisin, which was discovered by Husemann and
Marms in 1864.
A small dose of juice infused under the skin is quite sufficient to kill
a cat or a dog. Children have died from eating the seeds, of which ten
or twelve were sufficient to cause death. The worst of it is that there
is no remedy, no antidote against this poison. How many cases have
happened before the danger was discovered is of course only a matter of
conjecture, as few would suspect the cause to come from the lovely plant
that so delights the eye.
It has, however, long been known to gamekeepers and others, and used by
them to destroy "vermin." When quite a boy I remember an old uncle of
mine telling me to beware of it even in gathering the blossom.