state. The woman did not eventually recover until the following April. There was no doubt, from the 
investigation made by Dr. Ross and Dr. Christison, that her protracted illness was really due to the effects 
of the laburnum-bark. 
“ Some experiments were then made on the action of the poison on animals. A teaspoonful of the 
powder of dry laburnum-bark was administered to a cat. Soon afterwards it writhed, apparently in great 
pain ; in a short time it vomited violently, and, although languid and dejected for the rest of the day, it 
quickly recovered. Sixty-nine grains of the same powder were given to a dog. In ten minutes it whined 
and moaned, vomited violently, and soon got well. On a second occasion, twenty grains were found to act 
as a powerful emetic upon the animal. An ounce of the infusion of laburnum-bark, containing the active 
matter of sixty-two grains, was introduced by a catheter into the stomach of a full-grown rabbit. In ten 
minutes the animal looked quickly from one side to the other, twitched back its head twice or thrice, and 
instantly fell on its side in violent tetanic convulsions, with alternating emprosthotonos and opisthotonos, 
so energetic, that its body bounded with great force upon the side, up and down the room. Suddenly, 
however, all movement ceased, respiration was at an end, the whole of the muscles became quite flaccid, no 
sign of sensation could be elicited, and the animal died within two minutes and a half after the poison was 
injected into the stomach. The body was opened in two minutes more, and the heart was found gorged 
with blood, but contracting with some force. The stomach was filled with green pulp, soaked with the 
infusion. No morbid appearance was visible anywhere. In repeating this experiment, one rabbit died in 
half an hour, another in three quarters of an hour, after small doses of the infusion were injected into the 
stomach ; and a third rabbit speedily died after eating greens merely impregnated with the infusion. In 
all these instances convulsions were the leading symptoms produced. The same effects are popularly 
ascribed to the leaves, young pods, and seeds of the tree ; but no experiments have been performed with 
these. The facts here detailed show that laburnum-bark is a most energetic poison — as powerful, even, as 
nux vomica. 
“ Analysis. — There are no chemical means of detecting the nature of this poison, especially when 
administered in powder or infusion ; or when a decoction of the bark is given in food. A decoction of the 
bark yielded a clear light brown infusion with a slight acid reaction. It was not precipitated by albumen, 
or a solution of tartarized antimony; hence it contained no tannic acid. With a persalt of iron it acquired 
a dark greenish-brown colour, — of a deep red by transmitted light. Strong nitric acid caused it to acquire 
a lighter colour. It gave a very copious gelatinous precipitate with acetate of lead, which was almost 
entirely re-dissolved by acetic acid. On decomposing this precipitate by sulphuric acid, filtering and 
applying a persalt of iron to the filtered liquid, a greenish-brown precipitate fell (gallate of iron) without 
any red tint whatever. A much stronger decoction of the bark, as well as a decoction of the tops, yielded 
similar results. 
“The bark has been said to contain meconic acid; but these results prove that none of this peculiar acid 
is present. The only plan for determining with certainty the deleterious properties of the substance, would 
be by exhibiting a portion of the suspected decoction or infusion to animals. 
“ It has been recently announced that meconic acid is actually contained in the bark of the common 
laburnum tree, and that the iron-test strikes, with a decoction or infusion of this bark, a deep red colour, 
characteristic of meconic acid. The writer has further asserted that in testing for meconic acid, laburnum 
and laudanum would give precisely similar results. The improbability of laburnum bark or its decoction 
being found in the stomach, unless it had been intentionally administered as a poison, would be sufficient to 
take away the practical force of this objection, admitting it to be valid. 
“ Laburnum is a most powerful poison, and destroys life under symptoms widely different from those 
produced by opium; but the result of many experiments with the concentrated and diluted decoction and 
infusion of the bark procured in the metropolis as well as at a distance in the country, is that I have not 
been able to detect in it the slightest trace of meconic acid, or of any acid that could possibly be mistaken 
for it. The iron-test gives at first a deep reddish colour when added to the decoction, but this colour 
speedily changes to a dingy greenish-brown, instead of remaining of a clear red like the meconate of iron. 
It is quite certain that a person used to the analysis of opium could not mistake this chemical change for 
that produced by meconic acid. As tannic acid gives no precipitate with the decoction, the effect is pro- 
bably due to gallic acid combined or mixed with organic matter. The clear liquid obtained from a decom- 
position (by sulphuric acid) of the precipitate formed in the decoction by a salt of lead, did not acquire any 
red colour upon the addition of the iron-test. 
The deleterious properties of this plant (says Professor Burnett,) depend upon a peculiar proximate 
principle, discovered by MM. Chevalier and Lassaigne, and called by them Cytisine; small doses of it, 
when given to various animals, produce vomiting, convulsions, and death. The same principle, or a very 
similar one, appears to be present in the flowers of Arnica montana, (the Leopard’s bane;) and in Asarum 
Europeum, (the Asarabacca.) Notwithstanding the poisonous quality of the seeds, and the purgative effects 
of the young shoots, the latter form a very favourite food with hares and rabbits, who, it is said, will touch 
no other plant while a twig of laburnum remains; and hence it is frequently sown in plantations to protect 
young trees, until they are large enough to resist all leporine assaults. 
