Poisonous substances have been very differently arranged by different
authors, each appearing to have adopted a classification best suited to
promote the particular views and objects of his own pursuit; thus, the
botanist and chemist, engaged in the examination of the physical
characters by which poisons may be individually distinguished and
identified, have very judiciously erected their system upon the basis of
natural history. The pathologist, whose leading object is the
investigation of the morbid effects which follow the administration of
these agents, with equal propriety and justice prefers a classification
deduced from a generalization of the symptoms they are found to
occasion; while the physiologist, who seeks to ascertain through what
organs, and by what mechanism they destroy life, may be reasonably
expected to arrange the different poisons under divisions corresponding
with the results of so interesting an inquiry.
To meet the comprehensive views of the forensic toxicologist, an
arrangement would seem to be required, that should at once embrace the
several objects which we have just enumerated; for the data from which
the proof of poisoning is to be inferred, are, as we have often stated,
highly complicated in their relations. No such classification, however,
can be accomplished, and we are therefore compelled to select one which
may approach the nearest to our imaginary fabric. That which was
proposed by _Fodéré_,[210] and adopted, with some trivial alteration in
the order of succession of the classes, by _Orfila_, in his celebrated
system of toxicology, although it has many defects and some errors,
nevertheless merits the preference of the forensic physician; its basis
is strictly pathological, and yet it distributes the different poisons,
with some few and unimportant exceptions, in an order corresponding with
that of their natural history.
The first two classes, for instance, present us with substances of a
mineral origin; the third and fourth, with those which are principally
of a vegetable nature; and the sixth, with objects chiefly belonging to
the animal kingdom. The importance of acknowledging a division, which
has a reference to the three great kingdoms of Nature, is perhaps
greater than the reader may anticipate; for in enumerating the various
experiments to be instituted for the detection of poisons, we are, by
such an arrangement, enabled to bring together a connected series of
processes, nearly allied to, intimately connected with, and in some
respects, mutually dependant upon each other.
The following is the arrangement of _Fodéré_ as modified by _Orfila_:
viz. Cl. I, _Corrosive_, or _Escharotic poisons_. Cl. II, _Astringent
poisons_. Cl. III, _Acrid_ or _Rubefacient poisons_. Cl. IV, _Narcotic_
or _Stupefying poisons_. Cl. V, _Narcotico-Acrid poisons_. And Cl. VI,
_Septic_ or _Putrefying poisons_.
Class I. CORROSIVE or ESCHAROTIC POISONS. Such as corrode and burn the
textures to which they are applied. When internally administered they
give origin to the following symptoms: violent pain accompanied with a
sense of heat and burning in the stomach, and throughout the whole
extent of the alimentary canal; frequent vomitings, often sanguineous,
and alternating with bloody diarrhœa, with or without tenesmus; the
pulse hard, small, frequent, and at length imperceptible; an icy
coldness of the body; cold sweats; a great anxiety and oppression at the
præcordia; and hiccup. Sometimes the heat of the skin is intense, the
thirst inextinguishable, and the unhappy patient is tormented with
Dysuria and Ischuria, violent cramps in the extremities, and horrid
convulsions, which are relieved only by death. Such are the general
symptoms by which this species of poisoning is characterised; the
rapidity with which the symptoms terminate their course, will depend
upon the violence of the dose, and the particular species of poison
which has produced them; there are, moreover, other symptoms which will
be more conveniently described, when we come to speak of the effects of
corrosive poisons individually. In this class are ranked the following
substances. METALS. I. Arsenic—1. _Arsenious Acid_, or white oxide of
Arsenic. 2. _Arsenites_, or combinations of that acid with _salifiable
bases_. 3. _Arsenic Acid._ 4. _Arseniates_, or combination of the
preceding acid with the bases. 5. _Sulphurets of Arsenic_, or _Orpiment_
and _Realgar_. II. Mercury—1. _Corrosive Sublimate of Mercury_, or
_Oxy-muriate of Mercury_. 2. _Red Oxide of Mercury._ 3. _Red
Precipitate_, or _Nitric Oxide of Mercury_. 4. Other preparations of
Mercury. III. Antimony—1. _Tartarized Antimony_, or _Tartar Emetic_. 2.
_Oxide_ _of Antimony._ 3. _Antimonial Wine._ 4. _Muriate of Antimony_,
or _Butter of Antimony_. IV. Copper—1. _Blue Vitriol_, or _Sulphate of
Copper_. 2. _Verdegris._ 3. _Oxide of Copper._ 4. Other preparations of
Copper. V. Tin—1. _Muriate of Tin._ VI. Zinc—1. _Sulphate of Zinc_, or
_White Vitriol_. 2. _Oxide of Zinc._ VII. Silver—1. _Nitrate of Silver_,
or _Lunar Caustic_. The Concentrated Acids—1. _Sulphuric._ 2.
_Muriatic._ 3. _Nitric._ 4. _Phosphoric_, &c. Hot Liquids—1. _Boiling
water._ 2. _Melted Lead._ The Caustic Alkalies—1. _Potass._ 2. _Soda._
3. _Ammonia._ The Caustic Alkaline Earths—1. _Lime._ 2. _Baryta._ 3.
_Muriate_, and _Carbonate of Baryta_. Cantharides. Phosphorus.
Class II. ASTRINGENT POISONS. They occasion a remarkable and unrelenting
constriction of the great intestines, especially the colon, so as to
resist the operation of the most powerful cathartic remedies. Violent
cholics ensue, and partial paralysis; in the end if the dose be
sufficiently large, or if small doses have been frequently repeated,
they will excite inflammation of the alimentary canal, but it is not
succeeded by that disorganization which generally characterises the
operation of poisons, belonging to the preceding division. We rank under
the present class only the preparations of Lead, viz. 1, _Acetate of
Lead_, or _Sugar of Lead_; 2, _Oxides of Lead_; _Red Lead_; _Litharge_;
3, Various Saturnine impregnations.
Class III. ACRID, or RUBEFACIENT POISONS. These poisons are known by
their producing an acrid taste, more or less pungent and bitter; a
burning heat, and considerable dryness in the mouth and fauces; and a
constriction, more or less painful, in the throat. Acute pains are,
after a short interval, experienced in the stomach and bowels, which are
quickly followed by copious vomiting and purging, and which continue,
with the most painful efforts, long after the alimentary canal has been
completely evacuated. A few hours after, phenomena are observed which
indicate a lesion of the nervous system, such as vertigo, dilated
pupils, dejection, insensibility, laborious respiration, and death. The
lesions of texture, occasioned by the action of _Acrid_ poisons, have
the greatest analogy to those produced by _Corrosive_ poisons; in fact,
says _M. Orfila_, “we do not hesitate to declare, that there exists a
perfect identity between the alterations of the digestive canal produced
by the poisons of these two classes, when introduced into the stomach.”
The substances included under this class belong, for the most part, to
the vegetable kingdom, such as _Scammony_, _Camboge_, _Black_ and _White
Hellebore_, _Bryony_, _Euphorbium_, Seeds of the _Ricinus_, _Iatropa
Curcas_ (Indian nut), _Croton Tiglium_, _Squill_, _Aconite_, &c. &c.
Class IV. NARCOTIC, or STUPEFYING POISONS. Such as occasion stupor,
drowsiness, paralysis, or apoplexy, and convulsions. They do not produce
any change in the structure of parts to which they are applied. _M.
Orfila_ has satisfactorily ascertained that no alteration can be
discovered, on dissection, in the digestive canal of persons who have
swallowed any one of the poisonous substances of this class.
Class V. NARCOTICO-ACRID POISONS. This division, as its name implies, is
intended to receive such substances as produce the united effects of
those belonging to the two preceding classes, acting for instance at the
same time, as narcotics and rubefacients. Amongst the articles of this
class the following may be enumerated, _Belladonna_, _Stramonium_,
_Tobacco_, _Foxglove_, _Hemlock_, _Nux Vomica_, _Camphor_, _Cocculus
Indicus_, certain _Mushrooms_, _Alcohol_, &c. &c.
Class VI. SEPTIC and PUTREFYING POISONS. By this term are included those
poisons which, according to _Orfila_, “occasion a general debility,
dissolution of the humours, and syncope, but which do not, in general,
alter the intellectual faculties.” The articles of this class belong
almost entirely to the animal kingdom, with the exception perhaps of a
few gaseous compounds, and the _Spurred Rye_, or _Ergot_, viz. _venomous
animals_; _animals whose fluids have been depraved by antecedent
disease_; _the poison of fishes_; _substances in a state of putridity_;
_Spurred Rye_, or _Ergot_.
Such is the classification which, for reasons already stated, it is our
intention to adopt on the present occasion. We shall, however, in an
additional chapter, under the title of “_Aërial Poisons_,” treat of
those substances which are exclusively capable of acting upon the body
through the medium of the atmosphere, or which require to be in a state
of vapour, or gas, to ensure their operation.
With regard to the classification of _Fodéré_ and _Orfila_, we must here
observe that we follow it only conventionally, and that, while we
acknowledge it as being very convenient for the consideration of
poisons, in reference to their forensic relations, yet we must not be
considered as insensible to its many defects and fallacies. In the first
place, it has little or no reference to the enlarged views of the modern
physiologist, respecting the “_modus operandi_” of poisons; nor indeed
is its construction susceptible of such modifications and improvements,
as can ever render its degree of perfection progressive with the
advancement of science. In the next place, the classes are in many
particulars ill-defined, and indistinctly, if not erroneously, divided.
How questionable, for instance, are the boundaries which separate
_Corrosive_ from _Acrid_ poisons? even the respective species of each
class are, in many instances, less allied to each other than the great
divisions to which they are subordinate. As an exemplification of this
fact we have only to compare the physiological actions of _Arsenic_ and
_Corrosive Sublimate_; the former of these substances occasions death by
being absorbed, and thus acting as a vital agent, the latter, by its
local action as a caustic on the textures with which it comes in
contact. In the same manner, if we examine the individual actions of the
different species composing the class of “_Acrid_” poisons, we shall
find the same want of uniformity; thus the _Spurge-flax_, and the
_Jatropa Curcas_ act by occasioning a local inflammation, while the
_Hellebore_, being rapidly absorbed, exerts a fatal action on the
nervous system, and produces only a very slight inflammation. The class
of Narcotic poisons is more absolute in its definition, and more uniform
in its physiological affinities, and therefore less objectionable, than
the divisions to which we have just alluded; but the propriety of the
term “_Narcotico-Acrid_” may be very reasonably questioned;[211] even
_Orfila_ expresses his doubts upon the subject, “because the narcotic or
sedative effects only follow the previous excitement.” Some of the
poisons, under this last mentioned class, are rapidly absorbed, and act,
through the medium of the circulation, on the nervous system, without
producing any local inflammation; whilst others, again, merely act upon
the extremities of the nerves, with which they come in contact, and
without being absorbed, occasion death by a species of sympathetic
action.
These few objections, and many more might be adduced, are sufficient to
demonstrate the imperfection of the classification under consideration,
and which would render it wholly unavailable to the pathologist who must
adopt his treatment according to the physiological action of each
poison. The author has accordingly, in his “Pharmacologia”[212] ventured
to propose an arrangement, in conformity with such views; and the
following sketch of it may perhaps form a useful introduction to the
general observations which it will be hereafter necessary to offer upon
the “_modus operandi_” of poisons.
A CLASSIFICATION OF THE DIFFERENT MODES BY WHICH POISONS PRODUCE THEIR
EFFECTS.
† This mark denotes that the substance, against which it is placed, may
also act by being absorbed.
‡ Signifies that the article has also a local action.
I. BY ACTING THROUGH THE MEDIUM OF THE NERVES, WITHOUT BEING ABSORBED,
AND WITHOUT EXCITING ANY LOCAL INFLAMMATION.
a. _By which the functions of the nervous system are destroyed._
Acrid.
Aconite.
Jatropa Curcas.
Narcotico-Acrid.
Alcohol.
Oil of Tobacco.
Narcotic.
Essential Oil of Almonds.†
Camphor.†
Opium†?
b. _By rendering the heart insensible to the stimulus of the blood._
Infusion of Tobacco.
_Upas Antiar._
II. BY ENTERING THE CIRCULATION, AND ACTING THROUGH THAT MEDIUM WITH
DIFFERENT DEGREES OF FORCE, ON THE HEART, BRAIN, AND ALIMENTARY
CANAL.
Corrosive.
Arsenic.
Emetic Tartar.
Muriate of Baryta.
Acrid.
Hellebore.
Savine.
Meadow Saffron.
Squill.
Narcotic.
Opium.‡
Lettuce.
Henbane.
Prussic acid.
Narcotico-Acrid.
Deadly Nightshade.‡
Hemlock.
Camphor.‡
Cocculus Indicus.
III. BY A LOCAL ACTION ON THE MUCOUS MEMBRANE OF THE STOMACH, EXCITING
A HIGH DEGREE OF INFLAMMATION.
Corrosive.
Corrosive Sublimate.†
Verdegris.
Muriate and
Oxide of Tin.
Sulphate of Zinc.
Nitrate of Silver.
Acids.
Alkalies.
Cantharides.†
Acrid.
Bryony.
Elaterium.†
Colocynth.†
Camboge.
Euphorbium.
Hedge Hyssop.
Croton Tiglium.
Ranunculi.
The preceding classification of poisons will not only furnish the
practitioner with a general theorem for the administration of antidotes,
but it will suggest the different modes and forms of administration of
which each particular substance is susceptible; it will shew, that
certain poisons may occasion death without coming into contact with any
part of the alimentary canal, and that others will produce little or no
effect, however extensively they may be applied to an external surface.
The first class comprehends such poisons as operate, through the medium
of the nerves, upon the organs immediately subservient to life; in the
application of such agents it is obvious that they cannot require to be
introduced into the stomach, they may convey their destructive influence
by an application to any part duly supplied with nerves, and whose
extremities are exposed to their action; although at the same time, it
may be observed that, in general, poisons of this kind act most
powerfully when internally administered, owing to the extensive
sympathetic relations of this central organ over every function of the
living body. The second class consists of poisons that are incapable of
producing any effect, except through the medium of the circulation;
whence we shall be enabled to explain and appreciate the various
circumstances which may accelerate or retard their operation. Poisons of
this class may be applied externally to abraded parts, or even to
surfaces covered with cuticle, provided their absorption be promoted by
friction; and it may be here observed, that the function of absorption
is not performed with the same force in every tissue; as a general
proposition it may be said to be energetic in proportion to the number
of lymphatics and veins, although the late experiments of _M. Majendie_
have shewn how greatly it is influenced by the state of the
circulation.[213] If these poisons be administered internally, they find
their way into the circulating current either through the branches of
the thoracic duct, or those of the _venæ portarum_; when, as if by a
species of election, each substance very frequently expends its venom
upon some one particular system of organs. Many of the substances
arranged under this second division, have moreover a local effect upon
the structure with which they first come in contact; it is thus with
_Colocynth_, and some other bodies; while on the contrary, several of
those poisons which are distinguished for their _local action_, are
subsequently absorbed, and are thus as it were enabled to ensure their
work of destruction by a double mode of operation. We shall receive
ample evidence of this truth, as we proceed in the history of particular
poisons. The third class comprises such agents as inflict their
vengeance upon the mucous membrane of the stomach, by actual contact,
and destroy, by exciting local inflammation.
_MINERAL POISONS._
Under this head is included the greater proportion of those substances
which are employed as the instruments of crime; for they are generally
of easy access, require but little preparation, and are so destructive
in small doses, and, at the same time, so little disgusting in flavour,
as to furnish the assassin with the sure and secret means of
destruction. Fortunately, however, for the ends of justice, such agents
are pre-eminently the objects of successful analysis. In treating of the
history of the individual substances derived from this kingdom, we shall
consider, 1st. their _external characters_, such as form, colour, odour,
taste, specific gravity; 2d. their _chemical composition, and
habitudes_; 3d. _the tests by which their presence may be recognised_;
_4th. the symptoms which they occasion_; _5th. their physiological
action_; _6th. their different modes and forms of application_; _7th.
the lesions of structure they occasion_; _8th. the phenomena presented
on dissection_.
Cl. 1. CORROSIVE POISONS.