Treatise on Poisons by Sir Robert Christison
CHAPTER II.
1435 words | Chapter 14
ON THE EVIDENCE OF GENERAL POISONING.
This subject is purely medico-legal. It comprehends an account of the
various kinds of evidence by which the medical jurist is enabled to
pronounce whether poisoning in a general sense (that is, without
reference to a particular poison), is impossible, improbable, possible,
probable, or certain. It likewise comprises an appreciation of the
circumstances which usually lead the unprofessional, as well as the
professional, to infer correctly or erroneously a suspicion of such
poisoning.
Under the present head might likewise be included the history of
poisoning, the art of secret poisoning, and some other topics of the
like kind. But the want of proper documents, and the unmeasured
credulity which has prevailed on the subject of poisoning throughout all
ages down to very recent times, has entangled these subjects in so
intricate a maze of fable, that a notice of them, sufficiently detailed
to interest the reader, would be quite misplaced in this work.
On the art of secret poisoning, however, as having been once an
important object of medical jurisprudence, it might be expected that
some comments should here be offered. But really I do not see any good
reason for wading through the mass of credulous conjectures and
questionable facts, which have been collected on the subject, and which
have been copied into one modern work after another, for no other cause
than that they are of classic origin, or feed our appetite for the
mysterious. No one now seriously believes that Henry the Sixth was
killed by a pair of poisoned gloves, or Pope Clement the Seventh by a
poisoned torch carried before him in a procession, or Hercules by a
poisoned robe, or that the operation of poisons can be so predetermined
as to commence or prove fatal on a fixed day, and after the lapse of a
definite and remote interval. With regard to the noted instances of
secret poisoning, which occurred towards the close of the seventeenth
century in Italy and France, it is plain to every modern toxicologist,
from the only certain knowledge handed down to us of these events, that
the actors in them owed their success rather to the ignorance of the
age, than to their own dexterity. And as to the refined secrets believed
to have been possessed by them, it is sufficient here to say, that
although we are now acquainted with ten times as many and ten times as
subtle poisons as were known in those days, yet none exist which are
endowed with the hidden qualities once so universally dreaded.
The crime of poisoning, from its nature, must always be a secret one.
But little apprehension need be entertained of the art of secret
poisoning as understood by Toffana or Brinvilliers,[63] or as it might
be improved by a modern imitator. It seems to have escaped the attention
of those who have written on the subject, that the practice of such an
art requires the knowledge not only of a dexterous toxicologist, but
also of a skilful physician; for success must depend on the exact
imitation of some natural disease. It is only among medical men,
therefore, and among the higher orders of them, that a Saint-Croix can
arise now-a days. How little is to be dreaded on that head is apparent
from the domestic history of the European kingdoms for the last half
century, compared with their history some centuries ago. Few medical men
have even been suspected, and those few only upon visionary grounds, and
under the impulse of violent political feeling.[64] In one late instance
only, so far as I am aware, has it been proved that the physician’s art
was actually prostituted to so fearful a purpose; and the detection of
the crime in that case shows how difficult concealment will always be
wherever justice is administered rigorously, and medico-legal
investigations skilfully conducted.[65]
Two extraordinary incidents which happened lately in Germany may appear
at first sight at variance with these views. I allude to the cases of
Anna Margaretha Zwanziger and Margaretha Gottfried, which justly excited
much interest where they occurred, and are notorious to continental
toxicologists. Zwanziger, while serving as housekeeper in various
families in the territory of Bayreuth in Bavaria during the years 1808
and 1809, contrived to administer poison,—sometimes under the
instigation of mere revenge or spite, sometimes for the purpose of
clearing the way for her schemes of marriage with her masters,—to no
fewer than seventeen individuals in the course of nine months; and of
these three died.[66] Gottfried, a woman in affluent circumstances and
tolerable station in the town of Bremen, was even more successful. For
she pursued her criminal career undiscovered for fifteen years; and when
detected in 1828 had murdered actually fourteen persons, and
administered poison unsuccessfully to several others. Her motive, as in
the case of Zwanziger, was the mere gratification of a malevolent
temper, or the removal of supposed obstacles to her matrimonial dreams.
In neither of these instances, however, did the criminal possess any
particular skill, or observe much measure in her proceedings. The cases
of poisoning were of the common kind,—produced by arsenic,—proving in
general quickly fatal,—and presenting the ordinary phenomena. I cannot
help thinking, therefore, that the events now alluded to prove rather
the ineffectiveness of the police where they happened, than the
adroitness of the actors by whom they were brought about; and that they
constitute no sound objection to the statement, that the art of secret
poisoning is now unknown, and is not likely to be again revived.
It must be granted, indeed, that the late discoveries in chemistry and
toxicology have made poisons known which might be employed in such a way
as to render suspicion unlikely, and to baffle inquiry. But the methods
now alluded to are hitherto very little known; they cannot easily be
attempted on account of the rarity and difficult preparation of the
poisons; they can never be practised except by a person conversant with
the minute phenomena of natural disease; and it is no part of the object
of this work to make them public.
The evidence, by which the medical jurist is enabled to pronounce on the
existence or non-existence of poisoning in general, and to determine the
subordinate questions that relate to it, is derived from five
sources,—1, the symptoms during life; 2, the appearances in the dead
body; 3, the chemical analysis; 4, experiments and observations on
animals; and 5, certain moral circumstances, which are either
inseparably interwoven with the medical proof, or cannot be accurately
appreciated without medical knowledge.
SECTION I.—_Of the Evidence from Symptoms._
Not many years ago it was the custom to decide questions of poisoning
from the symptoms only. Till the close of last century, indeed, no other
evidence was accounted so infallible: and for the simple reason, that in
reality the other branches of evidence were even more imperfectly
understood. So lately as 1763, and even in Germany, the solemn opinions
of whole colleges were sometimes grounded almost exclusively on the
symptoms.[67] About that time, however, doubts began to be entertained
of the infallibility of such evidence; these doubts have since assumed
gradually a more substantial form; and it is now laid down by every
esteemed author in Medical Jurisprudence, that the symptoms, however
exquisitely developed, can never justify an opinion in favour of more
than high probability.[68] In laying down this doctrine medical jurists
appear to me to have injudiciously confounded together actual symptoms
with their general characteristics. If the doctrine is to be held as
applying to the evidence from symptoms, only so far as they are viewed
in questions of general poisoning,—that is, as applying to the general
characters merely of the symptoms,—it is deduced from accurate
principles. But if it is likewise to be applied, as recent authors have
done, to the actual symptoms produced by particular poisons, and in all
cases whatever of their action, then it is a rule clearly liable to
several important exceptions. These exceptions will be noticed under the
heads of the mineral acids, oxalic acid, arsenic, corrosive sublimate,
nux vomica, &c. At present it is only the general characters of the
symptoms, and the points in which they differ from the general
characters of the symptoms of natural disease, that I propose to
consider.
The chief characteristics usually ascribed to the symptoms of poisoning
considered generally, are, that they commence suddenly and prove rapidly
fatal,—that they increase steadily,—that they are uniform in nature
throughout their course,—that they begin soon after a meal,—and that
they appear while the body is in a state of perfect health.
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