OF POISONING WITH STRYCHNIA, NUX VOMICA, AND FALSE ANGUSTURA.
The next group of the narcotico-acrids includes a few vegetable poisons
that act in a very peculiar manner. They induce violent spasms, exactly
like tetanus, and cause death during a fit, probably by suspending the
respiration. But they do not impair the sensibility. During the
intervals of the fits the sensibility is on the contrary heightened, and
the faculties are acute.
Death, however, does not always take place by tetanus. In some cases the
departure of the convulsions has been followed by a fatal state of
general and indescribable exhaustion.
Besides thus acting violently on the nervous system, they also possess
local irritant properties; but these are seldom observed on account of
the deadliness and quickness of their remote operation on the spine and
nerves.
They exert their action by entering the blood-vessels. The dose required
to prove fatal is exceedingly small. The organ acted on is chiefly the
spinal cord; but sometimes they seem also to act on the heart.
They seldom leave any morbid appearances in the dead body. Like the
other causes of death by obstructed respiration, such as drowning and
strangling, they produce venous congestion; but this is frequently
inconsiderable. Sometimes, however, they leave signs of inflammation in
the alimentary canal.
Their energy resides in peculiar alkaloids. The only poisons included in
this group, are derived from the genus _Strychnos_. The bark of _Brucea
antidysenterica_ was long supposed also to possess similar properties;
but it is now known that the bark of _Strychnos nux-vomica_ was mistaken
for the bark of that tree.
Several species of _Strychnos_ have been examined, namely, the _S.
Nux-vomica_, the _S. Sancti Ignatii_ or St. Ignatius bean, the _S.
colubrina_, or snake-wood, the _S. tieuté_, which yields an Indian
poison the Upas tieuté, the _S. Guianensis_, and likewise the _S.
potatorum_ and _Pseudo-kina_; and all have been found to possess the
same remarkable properties, except the last two, which are inert.
All of them, except the _S. pseudo-kina_, and probably the _S.
potatorum_,[2323] contain an alkaloid to which their poisonous
properties are owing. This is _strychnia_ or strychnin, a substance
which has lately been made the subject of many experiments by chemists
and physiologists.
_Of Poisoning with Strychnia._
Strychnia was discovered by Pelletier and Caventou soon after the
discovery of morphia.[2324] For an account of the best process for
preparing it, the reader may consult a paper by M. Henry in the journal
quoted below.[2325]
Its leading properties are the following. Its crystals when pure are
elongated octaedres. It has a most intensely bitter taste, perceptible,
it is said, when a grain is dissolved in 80 pounds of water.[2326] It is
very sparingly soluble in water, but easily soluble in alcohol and the
volatile oils. Its alcoholic solution has an alkaline reaction. It forms
neutral and crystallizable salts with the acids. In its ordinary form it
is turned orange-red by the action of nitric acid; which tint becomes
violet-blue on the gradual addition of hydrosulphate of ammonia. The
action of nitric acid is owing to the presence of a yellow colouring
matter, or of another alkaloid, brucia, which is also contained in nux
vomica, but exists in larger quantity in the false angustura bark. Pure
strychnia is not turned orange-red by nitric acid.[2327]
No poison is endowed with more destructive energy than strychnia. I have
killed a dog in two minutes with a sixth part of a grain injected in the
form of alcoholic solution into the chest; I have seen a wild-boar
killed in the same manner with the third of a grain in ten minutes; and
there is little doubt that half a grain thrust into a wound might kill a
man in less than a quarter of an hour. It acts in whatever way it is
introduced into the system, but most energetically when injected into a
vein. The symptoms produced are very uniform and striking. The animal
becomes agitated and trembles, and is then seized with stiffness and
starting of the limbs. These symptoms increase till at length it is
attacked with a fit of violent general spasm, in which the head is bent
back, the spine stiffened, the limbs extended and rigid, and the
respiration checked by the fixing of the chest. The fit is then
succeeded by an interval of calm, during which the senses are quite
entire or unnaturally acute. But another paroxysm soon sets in, and then
another and another, till at length a fit takes place more violent than
any before it; and the animal perishes suffocated. The first symptoms
appear in 60 or 90 seconds, when the poison is applied to a wound. When
it is injected into the pleura, I have known them begin in 45 seconds,
and Pelletier and Caventou have seen them begin in 15 seconds.[2328] M.
Bouillaud has recently found that it has no effect when directly applied
to the nerves.[2329] The experiments of Mr. Blake tend to show, that its
action is exerted solely on the nervous system, and that it has no
direct action on the heart, even when directly admitted into the blood
by the jugular vein.[2330] It appears to act peculiarly by irritating
the spinal cord.
Dangerous effects have often been occasioned by an accidental over-dose
in ordinary medical practice. These are well exemplified by a case
communicated to Dr. Bardsley by Dr. Booth of Birmingham. A man of 46,
affected with hemiplegia for nearly four weeks, began to use strychnia,
and had been affected by it for eleven days without particular
inconvenience. During this period he took twice a day gradually
increasing doses, till the amount of one grain was attained; when the
usual physiological effect having ceased to occur, the quantity was
increased to a grain and a half. But the first dose caused anxiety and
excitability, in three hours stupor and loss of speech, and at length
violent tetanic convulsions, which proved fatal in three hours and
three-quarters.[2331] A fatal case, occasioned by the large dose of two
scruples, has been recorded by a German physician, Dr. Blumhardt. In
fifteen minutes, imperfect vomiting was brought on by emetics. At this
time, the patient, a lad of seventeen, lay on his back, quite stiff, and
with incipient fits of locked-jaw. The spasms gradually extended to the
rest of the body, till at last violent fits of general tetanus were
established, under which the whole body became as stiff as a board, the
arms spasmodically crossed over the chest, the legs extended, the feet
bent, so that the soles were concave, the breathing arrested, the
eyeballs prominent, the pupils dilated and not contractile, and the
pulse hurried and irregular. In the second severe fit he died, one hour
and a half after taking the poison.[2332] I have known very dangerous
tetanic spasm induced by so small a dose as two-thirds of a grain of the
ordinary impure strychnia of the shops; and Dr. Pereira describes a
case, communicated by a friend, where death was occasioned by a dose of
half a grain administered three times a day.[2333] As each fit of spasm
went off, respiration, which was found to have ceased, was maintained
artificially; but no sooner did natural breathing return, than the
paroxysm of tetanus returned also; and at length artificial inflation of
the lungs failed to restore life.
The only accounts I have seen of the morbid appearances after death from
strychnia are in the cases of Dr. Booth and Dr. Blumhardt. In the
former, the muscles were in a rigid state, the fingers contracted, the
vessels of the brain gorged, the membranes of the spinal cord highly
injected; and four patches of extravasated blood were found between the
spinal arachnoid and the external membrane. In the latter, twenty-four
hours after death, there was general lividity of the skin, and
extraordinary rigidity of the muscles. Fluid blood flowed in abundance
from the spinal cavity, where the veins were gorged, the pia mater
injected, the spinal column softened at its upper part, and here and
there almost pulpy. There was also congestion and softening of the
brain. The head and great vessels were flaccid, and contained scarcely
any blood. The inner membrane of the stomach and intestines presented
some redness, but not more than is often seen independently of
irritation there.
Strychnia has been found by Pelletier and Caventou in four species of
_Strychnos_, the _S. nux vomica_, _Sancti Ignatii_, _Colubrina_, and
_Tieuté_; and from the researches of MM. Martius and Herberger on the
composition and properties of the American poison Wourali, it is also
probably contained in the _S. guianensis_.[2334] Vauquelin could not
find it in the _S. pseudo-kina_, which is destitute of bitterness.
_Of Poisoning with Nux Vomica._
_Tests of Nux Vomica._—Nux vomica, the most common of these poisons, is
a flat, roundish seed, hardly an inch in diameter, of a yellowish or
greenish-brown colour, covered with short silky hair, and presenting a
little prominence on the middle of one of its surfaces. In powder it has
a dirty greenish-gray colour, an intensely bitter taste, and an odour
like powder of liquorice. It inflames on burning charcoal, and when
treated with nitric acid acquires an orange-red colour, which is
destroyed by the addition of protochloride of tin. Its infusion also is
turned orange-red by nitric acid, and precipitated grayish-white with
tincture of galls.
Orfila and Barruel have made some experiments on the mode of detecting
it in the stomach, and the following is the plan recommended by them.
The contents of the stomach, or the powder, if it can be separated, must
be boiled in water acidulated with sulphuric acid. The liquid after
filtration is neutralized with carbonate of lime, and then evaporated to
dryness. The dry mass is then acted on with successive portions of
alcohol, and evaporated to the consistence of a thin syrup. The product
has an intensely bitter taste, yields a precipitate with ammonia,
becomes deep orange-red with nitric acid, and will sometimes deposit
crystals of strychnia on standing two or three days.[2335] By this
process Dr. R. D. Thomson, in a case which proved fatal in three hours,
detected nux-vomica, although vomiting had been induced by
emetics.[2336]
These experiments it is important to remember, because, contrary to what
takes place in regard to vegetable poisons generally, nux vomica is
often found in the stomachs of those poisoned with it.
_Its Mode of Action and Symptoms in Man._—The poisonous properties of
nux vomica are now well known to the vulgar; and in consequence it is
occasionally made the instrument of voluntary death, although no poison
causes such torture. It is difficult to conceive, considering its
intensely bitter taste, how any one could make it the instrument of
murder. But a fact is stated in Rust’s Journal, which shows that it may
be used for that purpose. At a drinking party one man wagered with
another, that if he took a little _Cocculus indicus_ in beer, he would
be compelled to walk home on his head. The wager was taken and the
potion drunk; but nux vomica was substituted for the Cocculus indicus,
itself too a virulent poison; and the man went home and died in
convulsions fifteen minutes afterwards.[2337]
Many experiments have been made on animals with nux vomica; but the
first accurate inquiry was that of Magendie and Delille read before the
French Institute in 1809. The symptoms they remarked were precisely the
same with those produced by strychnia. Half a drachm of the powder
killed a dog in forty-five minutes, and a grain and a half of the
alcoholic extract thrust into a wound killed another in seven minutes.
The animals uniformly experienced dreadful fits of tetanic spasm, with
intervals of relaxation and sensibility, and were carried off during a
paroxysm.
The cause of death appears to be prolonged spasm of the thoracic muscles
of respiration. The spasm of these muscles is apparent in the unavailing
efforts which the animals make to inspire. The external muscles of the
chest may be felt during the fits as hard almost as bone; and, according
to an experiment of Wepfer, the diaphragm partakes in the spasm of the
external muscles.[2338]
On account of the singular symptoms of irritation of the spinal cord,
uncombined with any injury of the brain, this poison is believed to act
on the spinal marrow alone. This is farther shown by the experiments of
Mr. Blake with strychnia alluded to above. But from some experiments by
Segalas it appears also to exhaust the irritability of the heart: for in
animals he found that organ could not be stimulated to contract after
death, and life could not be prolonged by artificial breathing.[2339] A
similar observation was made long ago by Wepfer, who found the heart
motionless and distended with arterial blood in its left cavities;[2340]
and a case of poisoning in the human subject to the same effect will be
presently related. The pulse is always very weak, often wholly
suppressed during a paroxysm; and in the case alluded to it was found on
dissection pale, flaccid and empty, having been apparently affected with
spasm. The action exerted through the medium of the spinal cord on the
muscles is wholly independent of the brain; for Stannius found that in
frogs the removal of the brain does not interfere with the
effects.[2341]
Of late poisoning with nux vomica has been common. The most
characteristic example yet published is a case related by Mr. Ollier, of
a young woman, who in a fit of melancholy, took between two and three
drachms of the powder in water. When the surgeon first saw her, half an
hour afterwards, she was quite well. But going away in search of an
emetic, and returning in ten minutes, he found her in a state of great
alarm, with the limbs extended and separated, and the pulse faint and
quick. She then had a slight and transient convulsion succeeded by much
agitation and anxiety. In a few minutes she had another, and not long
afterwards a third, each about two minutes in duration. During these
fits, “the whole body was stiffened and straightened, the legs pushed
out and forced wide apart; no pulse or breathing could be perceived; the
face and hands were livid, and the muscles of the former violently
convulsed.” In the short intervals between the fits she was quite
sensible, had a feeble rapid pulse, complained of sickness with great
thirst, and perspired freely. “A fourth and most violent fit soon
succeeded, in which the whole body was extended to the utmost from head
to foot. From this she never recovered: she seemed to fall into a state
of asphyxia, relaxed her grasp, and dropped her hands on her knees. Her
brows, however, remained contracted, her lips drawn apart, salivary foam
issued from the corners of the mouth, and the expression of the
countenance was altogether most horrific.” She died an hour after
swallowing the poison.[2342]—A case precisely similar, produced by three
pence worth of the powder, and fatal in little more than an hour, is
related by Mr. Watt of Glasgow.[2343]—Another apparently also similar
but fatal in three hours, is related by Dr. R. D. Thomson.[2344] There
is in fact very little variety of symptoms in different cases, where
death occurs in the primary stage.—Occasionally even in such rapid cases
there is a little vomiting in the first instance. This was remarked in
Mr. Watt’s case, and also in another described by MM. Orfila and
Ollivier.[2345]
When death does not take place thus suddenly in a fit of spasm, the
person continues to be affected for twelve or sixteen hours with
similar, but milder paroxysms; and afterwards he may either recover
without farther symptoms, or expire in a short time apparently from
exhaustion, or suffer an attack of inflammation of the stomach and
intestines, which may or may not prove fatal.
M. Jules Cloquet has described a case, where the patient seemed to die
of the excessive exhaustion produced by the violent, long continued
spasms. The tetanic fits lasted about twenty-four hours, the sensibility
in the intervals being acute. Slight signs of irritation in the stomach
succeeded; and death ensued on the fourth morning.[2346]
In the Bulletins of the Medical Society of Emulation another case is
related, which arose from an over-dose of the alcoholic extract being
taken by an old woman who was using it for palsy. She took three grains
at once. Violent tetanus was soon produced; and afterwards she had a
regular attack of inflammation of the stomach and intestines, which
proved fatal in three days.
The last instance to be noticed exemplifies very well the effects of the
poison when the quantity is insufficient to cause death. A young woman
swallowed purposely a drachm mixed in a glass of wine. In fifteen
minutes she was seized with pain and heat in the stomach, burning in the
gullet, a sense of rending and weariness in the limbs succeeded by
stiffness of the joints, convulsive tremors, tottering in her gait, and
at length violent and frequent fits of tetanus. Milk given after the
tetanus began excited vomiting. She was farther affected with redness of
the gums, inflammation of the tongue, burning thirst, and pain in the
stomach. The pulse also became quick, and the skin hot. Next day, though
the fits had ceased, the muscles were very sore, especially on motion.
The tongue and palate were inflamed, and there was thirst, pain in the
stomach, vomiting, colic and diarrhœa. These symptoms, however, abated,
and on the fourth day disappeared, leaving her exceedingly weak.[2347]
This and the previous case show clearly the double narcotico-acrid
properties of the poison.
With regard to the dose requisite to prove fatal, the smallest fatal
dose of the alcoholic extract yet recorded is three grains, which was
the quantity taken in the case from the Parisian bulletins: Hoffmann
mentions a fatal case caused by two fifteen grain doses of the
powder;[2348] and in Hufeland’s Journal there is another caused by two
drachms, which was fatal in two hours.[2349]—A dog has been killed by
eight grains of the powder, and a cat by five.[2350] It is even said
that a dog has been killed by two grains.[2351]
It has been thought, from some observations by Mr. Baker on the
medicinal use of nux vomica in Hindostan that, by the force of habit,
the constitution may become to a certain extent accustomed to large
doses of this poison, in the same manner as it acquires the power of
enduring large doses of opium. The natives of Hindostan, often take it
morning and evening for many months continuously, beginning with an
eighth part of a nut, and gradually increasing the dose to an entire
nut, or about twenty grains. If it is taken either immediately before or
after meals, it never occasions any unpleasant effects; but if this
precaution be neglected, spasms are apt to ensue.[2352] As it is found
unsafe, however, to increase the dose beyond one nut, and the poison is
taken in the form of coarse powder, in which state it must be slowly
acted on by the fluid in the stomach, it is probable that the modifying
influence of habit is inconsiderable. Habit certainly does not
familiarize the system to strychnia used medicinally. The same dose,
which has once excited its peculiar physiological action, will for the
most part suffice to excite it again, however frequently the dose may be
repeated.—The facts mentioned by Mr. Baker show that nux vomica is not a
cumulative poison; and European experience, in the instance of
strychnia, is to the same effect.
_Morbid Appearances._—The morbid appearances differ according to the
period at which death occurs. In Mr. Ollier’s case, where death took
place in an hour, the appearances were insignificant. The stomach was
almost natural, the vessels of the brain somewhat congested, the heart
flaccid, empty, and pale. In the case in Hufeland’s Journal there was
general inflammation of the stomach, duodenum and part of the jejunum.
In Cloquet’s case, a slower one, there was very little appearance of
inflammation. In that from the Parisian bulletins, on the contrary, the
stomach was highly inflamed, the intestines violet-coloured, in many
places easily lacerated and apparently gangrenous. In an interesting
dissection of a case, which was quickly fatal,—that related by Orfila
and Ollivier, there was found much serous effusion on the surface of the
cerebellum, and softening of the whole cortical substance of the brain,
but especially of the cerebellum. Blumhardt too, found softening of the
cerebellum and congestion of the cerebral vessels, together with
softening of the spinal cord and general gorging of the spinal veins.
This is some confirmation of an opinion advanced not long ago in France
by Flourence and others, that nux vomica acts particularly on the
cerebellum.[2353] In Dr. R. D. Thomson’s case, which was examined by Mr.
Taylor, there was found much congestion of the whole membranes and
substance of the brain and cerebellum, and even some extravasation of
blood within the cavity of the arachnoid over the upper surface of the
former. Mr. Watt remarked in his case (sixty hours, however, after death
in summer) softening of the substance of the brain and the lumbar part
of the spinal cord.—In Orfila and Ollivier’s case the lungs were found
much gorged with black fluid blood.—In Blumhardt’s case the heart and
great vessels were entirely destitute of blood.—There is sometimes seen,
as in Dr. R. D. Thomson’s case, a brown powder lining the stomach, even
although vomiting may have occurred.
The body appears sometimes to retain for a certain period after death
the attitude and expression impressed on it by the convulsions during
life. In the instance mentioned by Orfila and Ollivier the muscles
immediately after death remained contracted, the head bent back, the
arms bent, and the jaws locked. This state may even continue for some
hours, so that the body appears to pass into the state of rigidity which
precedes decay, without also passing through the preliminary stage of
flaccidity immediately after death. In the case related by Mr. Ollier,
the body five hours after death “was still as stiff and straight as a
statue, so that if one of the hands was moved the whole body moved along
with it;” and in Blumhardt’s case the rigidity twenty hours after death
was unusually great. This state of rigidity, however, does not
invariably occur. On the contrary, in animals the limbs become very
flaccid immediately after death; but the usual rigidity supervenes at an
early period.[2354] In Dr. R. D. Thomson’s case flaccidity immediately
followed death.
_Treatment._—Little is known of the treatment in this kind of poisoning.
But it is of the greatest moment to evacuate the stomach thoroughly, and
without loss of time. Hence emetics are useful; but if the stomach-pump
is at hand it ought to be resorted to without waiting for the operation
of emetics. Torosiewicz describes the case of a young woman who, after
the usual symptoms had begun to appear in consequence of the
administration of a tea-spoonful of powder, recovered under the action
of an emetic followed by rhatany-root.[2355] When nux vomica is taken in
powder,—the most frequent form in which it has been used,—it adheres
with great obstinacy to the inside of the stomach. Consequently whatever
means are employed for evacuating the stomach, they must be continued
assiduously for a considerable time. If the patient is not attacked with
spasms in two hours, he will generally be safe.
M. Donné of Paris has stated that he has found iodine, bromine, and
chlorine to be antidotes for poisoning with the alkaloid of nux vomica,
as well as for the other vegetable alkaloids. Iodine, chlorine, and
bromine, he says, form with the alkaloid compounds which are not
deleterious,—two grains and a half of the iodide, bromide, and chloride
of strychnia, having produced no effect on a dog. Animals which had
taken one grain of strychnia or two grains of veratria, did not sustain
any harm, when tincture of iodine was administered immediately
afterwards. But the delay of ten minutes in the administration of the
antidote rendered it useless. In the compounds formed by these antidotes
with the alkaloids, the latter are in a state of chemical union, and not
decomposed. Sulphuric acid separates strychnia, for example, from its
state of combination with chlorine, iodine, or bromine, and forms
sulphate of strychnia, with its usual poisonous qualities.[2356] It
remains to be proved that the same advantages will be derived from the
administration of these antidotes in the instance of poisoning with the
crude drug, nux vomica, as in poisoning with its alkaloid.
In general little difficulty will be encountered in recognizing a case
of poisoning with nux vomica. _Tetanus_ or locked-jaw is the only
disease which produces similar effects. But that disease never proves so
quickly fatal as the rapid cases of poisoning with nux vomica; and it
never produces the symptoms of irritation observed in the slower cases.
Besides, the fits of natural tetanus are almost always slow in being
formed; while nux vomica brings on perfect fits in an hour or less. It
is right to remember, however, that nux vomica may be given in small
doses, frequently repeated, and gradually increased, so as to imitate
exactly the phenomena of tetanus from natural causes. Medical men will
be at no loss to discover, on reflection, how the preparations of this
drug may be rendered formidable secret poisons.
_Of Poisoning with the St. Ignatius Bean and Upas Tieuté._
The _Strychnos Sancti Ignatii_, or St. Ignatius bean, contains about
three times as much strychnia as nux vomica, namely, from twelve to
eighteen parts in the 1000. It is very energetic. Dr. Hopf has mentioned
an instance of a man, who was attacked with tetanus of several hours’
duration after taking the powder of half a bean in brandy, and who seems
to have made a narrow escape.[2357]
The _Strychnos tieuté_ is the plant which yields the Upas tieuté, one of
the Javanese poisons. This substance has been analyzed by Pelletier and
Caventou, and found to contain strychnia.[2358] From the experiments of
Magendie and Delille, the Upas tieuté appears to be almost as energetic
as strychnia itself.[2359] Mayer found that the bark of the plant which
yields it, when applied in the dose of fifty grains to a wound, killed a
rabbit in two hours and a half.[2360] Dr. Darwin has given an account of
its effects on the Javanese criminals, who used formerly to be executed
by darts poisoned with the tieuté. The account quoted by him is not very
authentic; yet it accords precisely with what would be expected from the
known properties of the poison. He says, that a few minutes after the
criminals are wounded with the instrument of the executioner, they
tremble violently, utter piercing cries, and perish amidst frightful
convulsions in ten or fifteen minutes.[2361]
_Of Poisoning with False Angustura Bark._
Besides these poisons of the genus Strychnos, the present group
comprehends another, of the same properties, which was once supposed to
be derived from a plant of a different family, the _Brucea
antidysenterica_.
A species of bark, commonly called the false angustura bark, was
introduced by mistake into Europe instead of the true angustura,
cusparia, or bark of the _Galipea officinalis_. It was long supposed to
be the bark of the _Brucea antidysenterica_; but it is now known to be
the bark of _S. nux vomica_.[2362] It is a poison of great energy. It
gave rise to so many fatal accidents soon after its introduction, that
in some countries on the continent all the stores of angustura were
ordered to be burnt. It contains a less proportion of strychnia, but
more of the alkaloid brucia than nux vomica, the seed of the plant.
According to Andral, brucia is twenty-four times less powerful than
strychnia;[2363] but the bark itself is as strong nearly as nux-vomica,
for Orfila found that eight grains killed a dog in less than two
hours.[2364]
The symptoms it induces are the same as those caused by nux vomica. They
are minutely detailed in a paper by Professor Emmert of Bern.[2365] It
appears that during the intervals of the fits the sensibility is
remarkably acute: a boy who fell a victim to it implored his physician
not to touch him, as he was immediately thrown into a fit. Professor
Marc of Paris was once violently affected by this poison, which he took
by mistake for the true angustura to cure ague. He took it in the form
of infusion, and the dose was only three-quarters of a liqueur-glassful;
yet he was seized with nausea, pain in the stomach, a sense of fulness
in the head, giddiness, ringing in the ears, and obscurity of vision,
followed by stiffness of the limbs, great pain on every attempt at
motion, locked-jaw, and impossibility of articulating. These symptoms
continued two hours; and abated under the use of ether and
laudanum.[2366]
Some interesting experiments were made by Emmert with this poison to
show that it acts on the spine directly, and not on that organ through
the medium of the brain. If an animal be poisoned by inserting the
extract of false angustura bark into its hind-legs after the spinal cord
has been severed at the loins, the hind-legs as well as the fore-legs
are thrown into a state of spasm; or if the medulla oblongata be cut
across and respiration maintained artificially, the usual symptoms are
produced over the whole body by the administration of it internally or
externally,—the only material difference being that they commence more
slowly, and that a larger dose is required to produce them, than when
the medulla is not injured. On the other hand, when the spinal cord is
suddenly destroyed after the symptoms have begun, they cease
instantaneously, although the circulation goes on for some
minutes.[2367]
The true angustura bark has a finer texture than the other, and is
darker coloured, aromatic, pungent, and less bitter. The ferro-cyanate
of potass causes in a muriatic infusion of the false bark a precipitate,
which is first green and then becomes blue; and the same reagent
converts into blue the reddish powder which lines the bark. No such
effects are produced on the true angustura bark. Nitric acid renders the
rusty efflorescence of the spurious bark deep dirty blue, but has no
such effect on the true bark; which, besides, never exhibits a yellow
efflorescence.
With the preceding poisons Orfila has arranged also some poisons used by
the American Indians; but, as in Europe they are mere objects of
curiosity, it is scarcely necessary to treat of them particularly here.
The most interesting and best known of them is the _wourali poison_ of
Guiana, variously called woorara, urari, or curare, by different
authors. It is believed to have been traced by Martius to a new species
of strychnos, the _S. guianensis_, and more recently by Dr. Schomburg to
a different species, the _S. toxicaria_ of that traveller. But the
action it exerts does not correspond exactly with what would be expected
of a plant belonging to that genus.
The effects of wourali have been investigated by Sir B. Brodie in the
Philosophical Transactions for 1811–12, in Orfila’s Toxicology, in
Magendie’s Memoir on Absorption, and in Fontana’s Traité des Poisons.
But the most detailed inquiry is that by Emmert, published in 1818. It
produces, not convulsions or spasm of the muscles, but on the contrary
paralysis, and probably occasions death in this way by suspending the
respiration, in the same way as hemlock and conia. According to Emmert’s
experiments the spine only is acted on, and not the brain also.[2368]
Some remarkable experiments were made in 1839 by Mr. Waterton, to show
the power of artificial respiration in accomplishing recovery from its
effects. After the animals had fallen down motionless from the action of
the poison introduced through a wound, and when the action of the heart
had become so feeble as not to affect the pulse, artificial respiration,
continued in one instance for seven hours and a half, and in another for
two hours, had the effect of restoring the animals to health.[2369]