concerned, it is by opposing obstacles to their course that we must
attempt to counteract or divert their influence; and that, in this
case, it is through the use of trees alone that we possess any power.
Thus reversely, as in the case just stated, the cutting down of trees
and forests has often been a serious cause of diseases in certain
countries, by admitting a malaria to particular spots; though it is
easy to see that where any given spot suffers from malaria, through
condensation or confinement, the clearing away of these would be the
remedy, by attaining a free ventilation. To detail the particular
modes in which remedies may be applied through this species of aid,
is obviously unnecessary, and not easy, as it must depend on local
circumstances, differing for each place; but I may remark, as an
example in illustration of my meaning, that where, as in many of the
narrow and prolonged valleys of Greece, the sea shore is a marsh,
the remedy would be to plant a screen of trees beyond it, and thus
to prevent the sea winds from passing into the interior. And thus
did the ancient Romans compel the planting of trees on the shores
of Latium, to check the current from the Pontine marshes; rendering
groves sacred, under heavy penalties, and enacting other laws with
the same intentions.
With respect to such temporary precautions in these cases [p054] as
may concern armies in the field, or in camps, it is plain that they
will depend on attention to the courses and seasons of the winds;
while it would be abundantly easy to accumulate, from the histories
of campaigns, the most fearful examples of mortality produced by
neglect of these and similar precautions, and even down to almost
the very date at which I am writing: and there can be no hesitation
in saying, that an intimate and accurate knowledge of every thing
which concerns the production and propagation of malaria, forms a
most important branch in that information necessary to a soldier,
and above all to the quarter-master-general’s department and the
medical staff: while, did I dare to record but a very small portion
of the mortality experienced, not only in our own armies, but in
those of Europe at large, during even the last war, from ignorance
or neglect on this subject, it would, I believe, be found that it
almost equalled the mortality produced by the actual collision of
war itself. Walcheren will not soon be forgotten; if we have ceased
to think of our mortal Havannah expedition; and if a French army at
Naples was diminished by twenty thousand men, out of twenty-four, in
four days, from this cause; if Orloff lost nearly his entire army in
Paros; if Hungary has more than once destroyed ten times the number
of men by fever that it did by the sword,—these are but trifles in
the mass of reasons for saying, that no subject can well be more
important, and no knowledge much more necessary to the commander of
an army.
Some other points relating to prevention may deserve a few words
of notice, before I pass from this subject; if here, also, I must
be brief. Not to repeat the cautions founded on what relates to
the power of evening and morning, it has been asserted that the
use of a gauze veil will prevent the effect of malaria; and it is
not improbable that the air accumulated within that, may have the
power of decomposing the poison: it is an opinion, at least, which
is universal among the people in Malta, and very general in Spain
and Portugal. It is also found that fires and smoke are useful, and
especially on military service; the experiment having been tried on
a very large scale by Napoleon before Mantua, and on a smaller one
in Africa, with the most perfect success. With respect to [p055]
personal precautions, it is universally recommended to use wine and
a good diet, and especially never to leave the house in the evening
in situations peculiarly insalubrious, without the previous use of
wine or spirits; whence the universal practice of Holland in this
respect. Thus, also, narcotics prevent its influence; whence the wide
use of tobacco, of which the salutary effects appear to be most amply
established.
As to the tropical countries, there is here also one important
remark, which, from the great neglect of the fact, and its ruinous
consequences, appear particularly to demand a statement in this
place. It is the universal experience of the inhabitants, that the
attack of malaria, or the production of fevers, is aided by the use
of a full or animal diet; by the use of some particular articles of
food, such as butter; by excess in eating, generally; and, above all,
by eating in the heat of the day. This is not merely well known to
the negroes, but the fact is distinctly stated to travellers, and the
caution urged, however often it has been neglected, and especially
by our own countrymen. Of this, in particular, Major Denham is a
strong testimony; while he attributes his own exclusive preservation
to his having rigidly followed the recommendations of the natives,
which were always urged with the greatest earnestness. And if we
examine the causes of death, in most cases, of our African travellers
especially, I think there will be strong reasons for believing that
their lives have often been sacrificed to this very negligence
or obstinacy; while it is most evident that Niebuhr’s party, in
particular, owed the loss of their lives to what may be safely called
gluttony: and it is to be suspected that this will also explain the
loss of Captain Tuckey’s party; while, with respect to nations, it
has long been known that the English, the Dutch, and the northern
voracious people in general, who habitually indulge themselves in the
customs of their original country as tropical colonists, have always
been greater sufferers from the effects of those climates than the
French and the Spaniards, and apparently from this very difference.
And there seems little doubt, generally, that the vegetable diet of
Africa and Hindostan is the best security against the evil influence
of those climates, and that the chief sufferings of our [p056] own
colonists arise from transferring to those situations their ancient
habits of full and free living.
As I must not prolong this subject much further, I shall now pass to
a few remarks, but very brief ones, on the geography of malaria as
it relates to those parts of the continent of Europe most frequented
by English travellers; not daring to take room for actual and
useful information on that head, but wishing to point out merely
the importance of such geographical knowledge to those persons, on
account of the hazards which they so universally incur from that
ignorance or neglect, and of the great mass of suffering, and also
of mortality, which has been the lot of persons who had resorted to
those climates as travellers, or migrating residents, from various
motives, and not unfrequently with views to health. How often health
has been lost where it was sought, will be but too apparent to any
one who has chanced to possess an extensive acquaintance of this
nature.
Of Italy I can but afford to say generally, that except at a very
few points where the Alps or Apennines reach the sea, the whole of
its shores are pestilential, and often to such a degree as to lead
to their entire desertion, more frequently to their abandonment
in summer. And to avoid wet lands, or low lands, is not always a
sufficient precaution; since the most pestilential parts of the
maremma of Tuscany are dry, and since the annual mortality of Sienna
from fevers, even without epidemics, is one in ten. In the north of
Italy, the great plain is similarly insalubrious; though the more
unhealthy district does not commence until we arrive at Mantua,
extending thence to the sea. Of the Mediterranean islands, I can
only afford room to say, that the same rule holds good as to the
sea coasts, while the entire of Greece in the same circumstances
is similarly unhealthy, and subject to autumnal fevers in as great
a degree as the worst parts of Italy. The same is true of Spain
and Portugal, and the same rule also will be a guide; namely, that
malaria is to be expected in all the flat grounds, even when under
cultivation, and at all the exits of rivers on the sea, even though
no marshes should be present: and if I were desirous to name any
tract of land in Spain peculiarly [p057] insalubrious, it would be
the province of Valencia; while Carthagena is almost invariably fatal
even to those who, as labourers, are compelled to resort to it for
the needful work of its port, even during a few days.
Of France, little as it has hitherto been suspected by those who,
associating the term malaria with Italy, have been accustomed to
consider it as peculiar to that country, it would scarcely be untrue
to say that it contains as large a portion of insalubrious territory
as Italy itself, and produces fever and disease of as great severity
and extent, not merely on its sea coasts, but over very extensive
tracts in its interior. And this insalubrity may be conjectured,
when there are entire districts in which the average of life does
not exceed twenty, and in which the entire people are diseased from
their births to their graves. Such tracts are found chiefly on the
course of the Loire, and some other of the great rivers; and among
them, Bresse in the Lyonnais, the plain of Forez, and Sologne in the
Orleannais, are of the most notorious; while the coasts of Normandy,
and the whole of low Britanny, are similarly subject to eternal
intermittents, or to epidemic seasons of autumnal fevers, amounting
to absolute pestilences. And how English families have suffered in
this country from the incautious choice of residences in such places,
will be easily ascertained by whoever shall be at the trouble of
making the necessary inquiries.
But as I dare not pursue this extensive subject, I can only suggest
to our countrymen the utility of making themselves acquainted with
this matter, and with this dangerous geography, before encountering
the hazards which await them; while to physicians I need still less
name the necessity of that knowledge, since it is so often their
duty to choose and recommend for their patients, and since no man
can feel much at his ease who finds that he has sent into a land of
malaria the patient who has already been suffering from its diseases,
or that where he speculates on the cure of a consumption, that
cure is attained through the death of the patient, at Avignon, or
at Poitiers, or Nantes, or in some or other of the numerous places
subject to this most fearful poison.
It remains only to give a brief enumeration of the diseases [p058]
which are the produce of malaria, and of the general condition of
the inhabitants in the countries subject to it. With respect to this
latter, the most remarkable general fact is the contracted duration
of life. In England, the average may, if not very accurately, and
indeed considerably under the mark, be taken at 50; and when in
Holland it is but 25, it follows that the half of human life is
at once cut off by this destructive agent. In the parts of France
to which I have alluded, it becomes as low as 22 and 20, and
Condorcet, indeed, has calculated it as low as 18. With this, very
few attain the age of 50; and in appearance and strength, this
term is equivalent to 80 in ordinary climates; while 40 forms the
general limit of extreme and rare old age. The period of age, indeed,
commences after 20; and it is remarked, in particular, that the
females become old in appearance immediately after 17, and have, even
at 20, the aspect of old women. In many places, even the children are
diseased from their birth; while the life which is dragged on by the
whole population, is a life of perpetual disease, and most frequently
of inveterate and incurable intermittents, or of a constant febrile
state, with debility, affections of the stomach, dropsy, and far more
than I need here enumerate.
While the countenances of the people in those countries are sallow
or yellow, and often livid, they are frequently so emaciated as
to appear like walking spectres, though the abdomen is generally
enlarged, in consequence either of visceral affections or dropsy.
With these, rickets, varices, hernia, and, in females, chlorosis,
together with scorbutic diseases, ulcers, and so forth, are common;
and it is even to be suspected that the cretinage may depend on this
cause, since goitre is also one of the results of malaria, and since,
in the Maremma of Tuscany, idiotism is a noted consequence of this
pestilential influence.
The general mental condition is no less remarkable; since it consists
in an universal apathy, recklessness, indolence, and melancholy,
added to a fatalism which prevents them from even desiring to better
their condition, or to avoid such portion of the evils around them
as care and attention might diminish: and while it is asserted that
even the moral character becomes [p059] similarly depraved, I prefer
a reference to Montfalcon for a picture which it would not be very
agreeable to transcribe.
As to the absolute or positive diseases, besides those which I have
already named, I need scarcely say that remittent and intermittent
fevers, under endless varieties and types, form the great mass; and
next in order to them, may be placed dysentery and cholera, together
with diarrhœa. To these I must also add, those painful diseases of
the nerves, of which sciatica stands foremost, and the remainder of
which may be ranked under the general term of neuralgia; and further,
a considerable number of inflammatory diseases of a more or less
remittent type, among which rheumatism under various forms is the
most general, and the intermittent ophthalmia the most remarkable.
Lastly, I must include the various paralytic affections; since
apoplexy is one of the primary and direct consequences of malaria, as
various paralytic affections are the produce of intermittent, or the
consequences of the diseases of the nerves which are associated with
it.
It is still a curious and interesting fact, that this poison affects,
in an analogous manner, many different animals, and appears, in
reality, to be the cause of all the noted endemics and remarkable
epidemics which occur in the agricultural animals in particular.
This has been noticed even by Livy: and in France and Italy it is
equally familiar that the severe seasons of fever among the people
are similarly seasons of epidemics to black-cattle and sheep,
while the symptoms are as nearly the same as they could be in the
circumstances, and the appearances on dissection also correspond.
Thus also does it appear probable, that the rot in sheep is actually
the produce of malaria, as is indeed the received opinion among
French veterinarians; while Mr. Royston has observed that the animals
of this class are subject to distinct intermittents.
And while it is not less familiar in the West Indies, and in Dominica
particularly, that dogs suffer from a mortal fever in the same
seasons and periods as the people, the epidemic always breaking out
in them first, I have the most unexceptionable medical evidence of
the occurrence of a regular and well-marked tertian in a dog; that
evidence consisting in the concurring decision of many surgeons, by
whom the case was [p060] frequently examined, during a very long
period. But it is time to terminate a paper, which, if it is but a
sketch of an important subject, will at least convey to those to
whom malaria has not hitherto been an object of attention, a general
notion of the leading particulars which appertain to its natural
history.
J. M.
_Elements of Chemistry, including the recent Discoveries and
Doctrines of the Science. By_ Edward Turner, M.D., F.R.S.E., &c.,
&c. _Edinburgh_, 1827.
This is a closely-printed octavo of 700 pages, and presents us with
something more original, clear, and accurate than we have lately met
with in modern chemistry. It comprehends a perspicuous view of the
present state of chemical science; and, as far as its limits admit,
the theoretical parts are, with some exceptions, well and distinctly
worked out; nor are the practical details of manipulation neglected,
though they evidently occupy a secondary place in our author’s
estimation. To the arrangement we must at once decidedly object—it is
indeed evident that Dr. Turner has pitched upon Dr. Thomas Thomson
as his _magnus Apollo_, and here and elsewhere the book is tainted
accordingly.
This work is divided into four principal parts;—the first relates
to what Dr. Turner, following his prototype, Dr. Thomson, calls
_imponderables_, and a definition of them follows, which leads
us to suggest the term _inexpressibles_, as equally appropriate.
But, waiving this objection, the details relating to them are well
and clearly given. Thus, after some prefatory remarks upon the
subject of caloric or heat, (we prefer the latter term, and cannot
allow its ambiguity,) its modes of communication are considered,
first, as being _conducted_ through bodies, and then as _radiating_
through free space. In regard to the theories affecting the
latter, our author wisely, as we think, prefers that of Prevost
to that of Pictet. The _effects_ of heat are next discussed, such
as _expansion_, including an account of the thermometer, and
of the relative capacities of bodies for heat; _liquefaction_,
_vaporisation_, _ebullition_, _evaporation_, and the _constitution of
gases_ and lastly, the sources of heat are mentioned, but the details
are referred to other parts of the work. [p061]
_Light_ is next treated of, but we think too hastily, and too much in
the abstract.
Now the subjects of heat and light are obviously of the utmost
importance to the chemical philosopher, and they are very extensive,
and intricate and difficult to treat of, inasmuch as the writer is
necessarily upon the confines of chemical and mechanical philosophy,
and should be expert in both. When, therefore, elementary works on
chemistry are so written and arranged as to serve as text-books for
lectures, and indexes of reference to more accurate information, we
can make due allowance for brevity; but when the subject is intended
to be formally and completely developed to the student, independent
of other ocular and oral aids, much more extensive description and
detailed explanation is required, than is to be found either in
our author’s “Elements,” or in any other analogous condensation of
chemistry. Dr. Henry understands the requisite mode of conveying
information in these cases better than most writers; and when he
takes pains, and speaks for himself, has the talent of being brief,
and at the same time minute, deep, and clear. Dr. Ure, as his
dictionary shows, is an eminent example of such a writer—_he_ of
course is neglected, where, as with our author, Dr. Thomson is in the
ascendant; but the article caloric, in his dictionary, will at once
explain and illustrate our meaning, and would furnish an admirable
foundation for a detailed essay or treatise upon the subject. So
extensive, indeed, are the precincts of chemistry now becoming, that
either our _systems_ must become very voluminous, or we must adopt
the plan, which to us appears preferable, of distinct treatises upon
different branches of the science. Thus, a separate work on heat and
light; another on electricity and magnetism; another on attraction
and the theory of combination; a fourth on the constitution and
properties of the unmetallic elementary bodies; a fifth on the metals
and their compounds; a sixth on vegetable, and a seventh on animal
chemistry and physiology; an eighth on the chemistry of the arts;
and lastly, a treatise on chemical manipulation in general, would
include all that appears essentially requisite; and as no one is
supposed to be equally well versed in all branches of the science, or
in all details of the art, an opportunity of selection would thus be
afforded, so that each writer might choose that particular department
which he is most accurately acquainted with, or which has formed
his favourite study. Mr. Faraday has already, as may be said, led
the way in such a plan, by the publication of his _Chemical [p062]
Manipulation_, a work hitherto exceedingly wanted in the laboratory,
equally useful to the proficient and to the student, and eminently
creditable to the industry and skill of the author, and to the school
whence it emanates. We shall of course take an early opportunity of
introducing this book in a more formal way to the attention of our
chemical readers.
In looking over Dr. Turner’s first and second sections on caloric and
light, in the _Elements_ now before us, we find little but brevity
to complain of;—there are, however, one or two trifling historical
inaccuracies: thus, at page 14, the discovery of _invisible_ heating
rays is ascribed to Saussure and Pictet; but it is, in fact, of much
more remote origin—it was well known to the Florentine academicians,
and we may even trace the idea in Lucretius, (_De Rerum Naturâ_, lib,
v. 1, 609.)
Forsitan et rosea Sol alte lampade lucens
Possideat multum _cæcis fervoribus ignem_
Circum se, _nullo qui sit fulgore notatus, &c._
At page 31 we have an account of Wedgwood’s pyrometer, which is said
to be “little employed at present, because its indications cannot be
relied on;”—the fact is, that it is never used, and that we owe to
Sir James Hall ample reasons for placing no confidence in it.
The subject of _specific heat_ is clearly explained, and so are
the phenomena of liquefaction and evaporation. In regard to the
constitution of gases, the author remarks, that the experiments
of Sir H. Davy and Mr. Faraday on the liquefaction of gaseous
substances, appear to justify the opinion that gases are merely the
vapours of extremely volatile liquids. Mr. Faraday has proved this
in regard to several of the gases, and analogy leads us to apply it
to the rest;—but what share Sir H. Davy had in the discovery, we
know not; for Mr. Faraday actually condensed chlorine into a liquid
before Sir H. had heard or thought about the matter. _Light_, and
its phenomena as connected with chemistry, is superficially passed
over in the second section, and the third brings us to the important
article “Electricity.”