He who is governed by preconceived opinions, may be compared to a
spectator who views the surrounding objects through coloured glasses,
each assuming a tinge similar to that of the glass employed; thus have
crowds of inert and insignificant drugs been indebted to an ephemeral
popularity, from the prevalence of a false theory; the celebrated
hypothesis of Galen respecting the virtues and operation of medicines,
may serve as an example; it is a web of philosophical fiction, which was
never surpassed in absurdity. He conceives that the properties of all
medicines are derived from what he calls their elementary or _cardinal_
qualities, HEAT, COLD, MOISTURE, and DRYNESS. Each of these qualities is
again sub-divided into four degrees, and a plant or medicine, according
to his notion, is cold or hot, in the first, second, third, or fourth
gradation; if the disease be hot, or cold in any of these four stages, a
medicine possessed of a contrary quality, and in the same proportionate
degree of elementary heat or cold, must be prescribed. Saltness,
bitterness, and acridness depend, in his idea, upon the relative degrees
of heat and dryness in different bodies. It will be easily seen how a
belief in such an hypothesis must have multiplied the list of inert
articles in the materia medica, and have corrupted the practice of
physic. The variety of seeds derived its origin from this source, and
until lately, medical writers, in the true jargon of Galen, spoke of the
_four_ greater and lesser _hot_ and _cold_ seeds; and in the London
Dispensatory of 1721, we find the powders of _hot_ and _cold_ precious
stones, and those of the _hot_ and _cold_ compound powders of pearl.
Several of the ancient combinations of opium, with various aromatics,
are also indebted to Galen for their origin, and to the blind influence
of his authority for their existence and lasting reputation. Galen
asserted that opium was _cold in the fourth degree_, and must therefore
require some corresponding hot medicine to moderate its frigidity.[37]
THE METHODIC SECT, which was founded by the Roman physician
Themison,[38] a disciple of Asclepiades, as they conceived all diseases
to depend upon _overbracing_, or on _relaxation_, so did they class all
medicines under the head of _relaxing_ and _bracing_ remedies; and
although this theory has been long since banished from the schools, yet
it continues at this day to exert a secret influence on medical
practice, and to preserve from neglect some unimportant medicines. The
general belief in the relaxing effect of the _warm_, and the equally
strengthening influence of the _cold_ bath, may be traced to conclusions
deduced from the operations of hot and cold water upon parchment and
other inert bodies.[39]
THE STAHLIANS, under the impression of their ideal system, introduced
_Archœal_ remedies, and many of a superstitious and inert kind; whilst,
as they on all occasions trusted to the constant attention and wisdom of
nature, so did they zealously oppose the use of some of the most
efficacious instruments of art, as the Peruvian _bark_; and few
physicians were so reserved in the use of general remedies, as bleeding,
vomiting, and the like; their practice was therefore imbecile, and it
has been aptly enough denominated, “_a meditation upon death_.” They
were however vigilant in observation and acute in discernment, and we
are indebted to them for some faithful and minute descriptions.
THE MECHANICAL THEORY, which recognised “_lentor and morbid viscidity of
the blood_,” as the principal cause of all diseases, introduced
attenuant and diluent medicines, or substances endued with some
mechanical force; thus Fourcroy explained the operation of mercury by
its specific gravity,[40] and the advocates of this doctrine favoured
the general introduction of the preparations of iron, especially in
schirrus of the spleen or liver, upon the same hypothetical principle;
for, say they, whatever is most forcible in removing the obstruction,
must be the most proper instrument of cure; such is _Steel_, which,
besides the attenuating power with which it is furnished, has still a
greater force in this case from the _gravity_ of its particles, which,
being seven times specifically heavier than any vegetable, acts in
proportion with a stronger impulse, and therefore is a more powerful
deobstruent. This may be taken as a specimen of the style in which these
mechanical physicians reasoned and practised.
THE CHEMISTS, as they acknowledged no source of disease but the presence
of some hostile acid or alkali, or some deranged condition in the
chemical composition of the fluid or solid parts, so they conceived all
remedies must act by producing chemical changes in the body. We find
Tournefort busily engaged in testing every vegetable juice, in order to
discover in it some traces of an acid or alkaline ingredient, which
might confer upon it medicinal activity. The fatal errors into which
such an hypothesis was liable to betray the practitioner, receive an
awful illustration in the history of the memorable fever that raged at
Leyden in the year 1699, and which consigned two thirds of the
population of that city to an untimely grave; an event which, in a great
measure, depended upon the Professor Sylvius de la Boe, who having just
embraced the chemical doctrines of Van Helmont, assigned the origin of
the distemper to a prevailing acid, and declared that its cure could
alone be effected by the copious administration of absorbent and
testaceous medicines; an extravagance into which Van Helmont, himself,
would hardly have been betrayed:—but thus it is in Philosophy, as in
Politics, that the partisans of a popular leader are always more
sanguine, and less reasonable, than their master; they are not only
ready to delude the world, but most anxious to deceive themselves, and
while they warmly defend their favourite system from the attacks of
those that may assail it, they willingly close their own eyes, and
conceal from themselves the different points that are untenable; or, to
borrow the figurative language of a French writer, they are like the
pious children of Noah,[41] who went backwards, that they might not see
the nakedness which they approached for the purpose of covering.
Unlike the mechanical physicians, the chemists explain the beneficial
operation of iron by supposing that it increases the proportion of red
globules in the blood, on the erroneous[42] hypothesis that iron
constitutes the principal element of these bodies. Thus has iron, from
its acknowledged powers, been enlisted into the service of every
prevailing hypothesis; and it is not a little singular, as a late writer
has justly observed, that theories however different, and even adverse,
do nevertheless often coincide in matters of practice, as well with each
other as with long established empirical usages, each bending as it
were, and conforming, in order to do homage to truth and experience. And
yet iron, whose medicinal virtues have been so generally allowed, has
not escaped those vicissitudes in reputation which almost every valuable
remedy has been doomed to suffer: at one period the ancients imagined
that wounds inflicted by iron instruments, were never disposed to heal,
for which reason Porsenna, after the expulsion of the Tarquins, actually
stipulated with the Romans that they should not use iron, except in
agriculture; and Avicenna was so alarmed at the idea of its internal use
as a remedy, when given in substance, that he seriously advised the
exhibition of a magnet[43] after it to prevent any direful consequences.
The fame even of Peruvian bark has been occasionally obscured by the
clouds of false theory some condemned its use altogether, “because it
did not evacuate the morbific matter,” others, “because it bred
obstructions in the viscera,” others again, “because it only bound up
the spirits, and stopped the paroxysms for a time, and favoured the
translation of the peccant matter into the more noble parts.” Thus we
learn from Morton,[44] that Oliver Cromwell fell a victim to an
intermittent fever, because the Physicians were too timid to make a
trial of the bark. It was sold first by the Jesuits for its weight in
silver;[45] and Condamine relates that in 1690, about thirty years
afterwards, several thousand pounds of it lay at Piura and Payta for
want of a purchaser.
Nor has Sugar escaped the venom of fanciful hypothesis. Dr. Willis
raised a popular outcry against its domestic use, declaring that “it
contained within its particles a secret acid—a dangerous
sharpness,—which caused scurvys, consumptions, and other dreadful
diseases.”[46]
Although I profess to offer merely a few illustrations of those
doctrines, whose perverted applications have influenced the history of
the Materia Medica, I cannot pass over in silence that of John Brown,
“the child of genius and misfortune.” As he generalized diseases, and
brought all within the compass of two grand classes, those of
_increased_ and _diminished_ excitement, so did he abridge our remedies,
maintaining, that every agent which could operate on the human body was
a _Stimulant_, having an identity of action, and differing only in the
degree of its force; so that, according to his views, the lancet and the
brandy bottle were but the opposite extremes of one and the same class:
the mischievous tendency of such a doctrine is too obvious to require a
comment.
But the most absurd and preposterous hypothesis that has disgraced the
annals of medicine, and bestowed medicinal reputation upon substances of
no intrinsic worth, is that of the DOCTRINE OF SIGNATURES, as it has
been called, which is no less than a belief that _every natural
substance which possesses any medicinal virtue, indicates by an obvious
and well-marked external character, the disease for which it is a
remedy, or the object for which it should be employed_![47] This
extraordinary monster of the fancy has been principally adopted and
cherished by Paracelsus, Baptista Porta, and Crollius, although traces
of its existence may be certainly discovered in very ancient authors.
The root of the _Mandrake_, from its supposed resemblance to the human
form, was esteemed as a remedy for Sterility: thus did Rachael demand
from her sister the Mandrakes (_Dudaim_) which Reuben had gathered in
the field; impressed, as it would appear, with a belief in the efficacy
of that plant against barrenness.[48] There would moreover appear in
this case to have been some idea of additional virtue arising from the
person who gathered it, for great stress was laid upon this
circumstance, “_my son’s_ Mandrakes:” such a notion is by no means
uncommon in the history of charms. The supposed virtues of the _Lapis
Ætites_, or _Eagle stone_,[49] described by Dioscorides, Ætius and
Pliny, who assert that if tied to the arm it will prevent abortion, and
if fixed to the thigh forward delivery, were, as we learn from ancient
authority, solely suggested by the manner in which the nodule contained
within the stone moves and rattles, whenever it is shaken. “_Ætites
lapis agitatus, sonitum edit, velut ex altero lapide prægnans._” The
conceit however did not assume the importance of a theory until the end
of the fourteenth century, at which period we find several authors
engaged in the support of its truth, and it will not be unamusing to
offer a specimen of their sophistry; they affirm, that since man is the
lord of the creation, all other creatures are designed for his use, and
_therefore_, that their beneficial qualities and excellencies must be
expressed by such characters as can be seen and understood by every one;
and as man discovers his reason by speech, and brutes their sensations
by various sounds, motions, and gestures, so the vast variety and
diversity of figures, colours, and consistencies, observable in
inanimate creatures, is certainly designed for some wise purpose. It
_must be_, in order to manifest these peculiar qualities and
excellencies, which could not be so effectually done in any other way,
not even by speech, since no language is universal. Thus, the lungs of a
fox must be a specific for asthma, _because_ that animal is remarkable
for its strong powers of respiration. _Turmerick_ has a brilliant yellow
colour, which indicates that it has the power of curing the jaundice; by
the same rule, _Poppies_ must relieve diseases of the head; _Agaricus_
those of the bladder; _Cassia fistula_ the affections of the intestines,
and _Aristolochia_ the disorders of the uterus: the polished surface and
stony hardness which so eminently characterise the seeds of the
_Lithospermum Officinale_ (Common Gromwell) were deemed a certain
indication of their efficacy in calculous and gravelly disorders; for a
similar reason the roots of the _Saxifraga Granulata_ (White Saxifrage)
gained reputation in the cure of the same disease; and the _Euphrasia_
(Eye-bright) acquired fame, as an application in complaints of the eye,
because it exhibits a black spot in its corolla resembling the pupil.
In the curious work of _Chrysostom Magnenus_, we meet with a whimsical
account of the _Signature_ of Tobacco. “In the first place,” says he,
“the manner in which the flowers adhere to the head of the plant
indicates the _Infundibulum Cerebri_, and _Pituitary Gland_. In the next
place, the three membranes of which its leaves are composed announce
their value to the stomach which has three membranes.”[50]
The blood-stone, the _Heliotropium_ of the ancients, from the occasional
small specks or points of a blood red colour exhibited on its green
surface, is even at this day employed in many parts of England and
Scotland, to stop a bleeding from the nose; and nettle-tea continues a
popular remedy for the cure of _Urticaria_. It is also asserted that
some substances bear the SIGNATURES of the humours, as the petals of the
red rose that of the blood, and the roots of rhubarb and the flowers of
saffron, that of the bile.[51]
I apprehend that John of Gaddesden, in the fourteenth century,
celebrated by Chaucer, must have been directed by some remote analogy of
this kind, when he ordered the son of Edward the First, who was
dangerously ill with the small-pox, to be wrapped in scarlet cloth, as
well as all those who attended upon him, or came into his presence, and
even the bed and room in which he was laid were covered with the same
drapery; and so completely did it answer, say the credulous historians
of that day, that the Prince was cured without having so much as a
single mark left upon him.
In enumerating the conceits of Physic, as relating to the Materia
Medica, we must not pass over the idea, so prevalent at one period, that
_all poisonous substances possess a powerful and mutual elective
attraction for each other_; and that consequently, if a substance of
this kind were suspended around the neck, it would, by intercepting and
absorbing every noxious particle, preserve the body from the virulence
of contagious matter. Angelus Sala, accordingly, gives us a formula for
what he terms his _Magnes Arsenicalis_, which he asserts will not only
defend the body from the influence of poison, but will, from its powers
of attraction, draw out the venom from an infected person. In the
celebrated plague of London, we are informed that amulets of arsenic
were upon this principle suspended over the region of the heart, as a
preservative against infection.
There is yet to be mentioned another absurd conceit which long existed
respecting the subject of Antidotes,—a belief that every natural poison
carried within itself its own antidote; thus we learn from the writings
of Dioscorides, Galen, and Pliny, that the _virus_ of the _Cantharis
Vesicatoria_ existed in the body of the fly, and that the head, feet,
and wings, contained its antidote; for the same potent reason were the
hairs of the rabid dog esteemed the true specific for Hydrophobia.[52]