Chapter X: On the Servitude of Rivers

If the servitude of rivers be the noblest and most important victory which man has obtained over the licentiousness of nature,[55] then assuredly ancient civilizations bear away the palm in this respect from the modern, and Britain must be permitted to occupy perhaps the lowest place in the scale of those empires and nations who, by their industry and knowledge, overcame the difficulties which the right management of river courses presents to civilized man.

[55] “Decline and Fall,” vol. iii. p. 391, Milman’s edition.

More than forty centuries ago the Nile was completely at the service of the ancient Egyptians, and the prosperity of Babylon and Nineveh leaves no doubt as to the subjugation of the Tigris and the mighty Euphrates. To come to later times, the Rhine itself, even in the days of the early Roman emperors, must have been subjugated by the labours of the primitive Batavians, and the revolt of Civilis, with his Batavian legions, testifies as to the energy and intelligence of the race. And now by the patient industry of their descendants, that land, seemingly doomed by nature to be wasted on one side by the turbulent ocean, on the other by the great rivers which traverse it, presents a spectacle unequalled in the world. Even the despised Oriental race of China, that unsolved problem in the history of mankind, whose capital the combined forces of England and France now threaten, seems never to have had a difficulty in mastering the great problems which the necessity for the subjugation of rivers forces on civilized man; the Chinese waters have been turned to the most profitable account; their deltas seem healthy, and abound with life, with Chinese life, at least. The great rivers of the Celestial empire give no trouble to its inhabitants; agriculture is said to be perfect; no one seems to have proposed to throw the refuse of Pekin into the nearest stream, that stream too, as it might happen to be, the source from which the inhabitants of the capital obtain the water required for their manufactures and for the arts of life.[56]

[56] The idea of employing the drainage of towns, partaking under
all circumstances more or less of the nature of sewage--using the
term in its most extensive sense, as comprising the excreta of the
entire population--seems first to have originated in Scotland, and
especially in the vicinity of the capital. The period is perhaps not
well known, but about the commencement of the present century we find
the system in full force, but limited to the great outlets of the
drainage and soiled water of the town. These great drains were not
strictly speaking sewers, but drains, for at that time there were
but few sewers, properly so called. If cesspools existed, they were
not emptied into the drains, or so-called town-sewers, so that the
matters contained in the two great outlets used for the purposes of
_foul-water irrigation_ bore little or no resemblance to the turbid,
frightful, and most putrescent mass _now_ conveyed into the Thames by
the sewers of London. This essential distinction in the quality of
the material has been ignored or passed over in the Reports of the
Board of Health. Not that the irrigating water was to be considered
as pure; on the contrary, it was extremely filthy; but it did not
_at that time_ contain the sewage of the town, properly speaking. It
probably now does so in consequence of the extension of the system of
water-closets, latrines, &c. The Scotch agriculturists who employed
the water of these vast foul drains, would have much preferred _pure
water_, but they had it not at their command. With this, such as
it was, they irrigated certain tracts of land, some of which were
originally barren wastes, converting them into meadows on which grew
a peculiar kind of grass, which cattle (milch cows) do not reject
after having been accustomed to its use. But the farmers knew well
that the abominable liquid they thus poured over their fields was
wholly unfit for the usual agricultural purposes; and thus in no
instance did they employ it as manure. The Grange drain was used
by one market-gardener only, simply for the purposes of irrigation
during droughts, but not with any view to the manuring of the garden.
By the time that all the cesspools of London have been poured into
the drains, and the system of drainage and sewage completed and
formed into one system, there arises the question as to how the
material is to be disposed of? The pouring it into the Thames at a
point below the influence of the tide is perhaps, after all, the
easiest and least expensive mode of escaping from the dilemma into
which the capital has been brought by the clumsy experiments of the
late Board of Health; but what the ultimate result of this additional
experiment may be, no one can foretel. If transmitted to the fields,
the farmers are sure to reject it as manure; but it might be conveyed
to barren waste lands, mere sandy wastes, the qualities of which no
doubt in time it would beneficially affect, converting them first
into meadows, and possibly afterwards into land favourable for the
growth of certain green crops. The liquid might also be conveyed to
estuaries which it might be desirable to fill up, and the numerous
small tidal harbours which the extension of railways will speedily
render of little or no value to the inhabitants.

The mud deposited in tidal harbours or on the banks of rivers within
the influence of the tide is of no value as a manure; when spread
over the fields, the result is the loss of the crops for some years.

Civilization on the banks of the Thames is no doubt very different and very superior to what it possibly can be on the banks of the Yellow River, but as, _non omnia possumus_, as different races and nations, like individuals, have each their peculiar excellences and forms of civilization, excelling in some, deficient in other qualities of mind and body, it may undoubtedly happen that even the English of the present day, the most perfectly civilized nation on the earth, or that ever lived, might take a hint from some other nations on points respecting which their otherwise inimitable genius seems to show some slight deficiencies. As regards art, for example, we owe some hints to the pitiful States of ancient Athens and Corinth; the despicable Copt had connected the Mediterranean and Red Sea by a canal--the art of re-opening which seems now to be lost; even the miserable native Peruvian and Mexican had carried the arts of mining, of irrigation, and the use of artificial manures, to an extent which surprises the men of modern times, who, in Britain at least, think that civilization really only appeared in the world during the reign of Queen Anne, as in France the era of the Grand Monarque is universally admitted to be the period when the French nation first threw off its primitive barbarous and Celtic form of civilization, assuming the character and social habits of that race to whom they owe their name, though not their descent. If we cast our eyes over the surface of the earth, aided by the lights, somewhat obscure, no doubt, of history, certain facts rising above the ocean of detail appear as landmarks. The philosophic historian points to, as peculiarly within his province, the transfer of the seat of power from nation to nation, from race to race; how before Alexander appeared there seemed to have been a Sesostris; after the son of Philip came Julius the Dictator; then Napoleon; and drawing conclusions as to the future from the past, historians see no improbability, at least no impossibility, in New Zealand, after the lapse of many centuries, producing the Hume of the southern hemisphere; whilst a future capital arising in the desert regions of Siberia or Northern America, may one day dictate to the world.[57] Ever at variance as to the rise and fall of empires, they are yet agreed as to certain facts and circumstances, many of which are still verifiable by the geographical distribution of the existing rivers and mountain regions of the globe; and even if man, in the plenitude of his scepticism, were disposed to doubt, monuments exist, the undeniable work of human hands, under circumstances implying the existence of a social system which cannot well be misunderstood. “In the boundless annals of time, man’s life and labours must equally be measured as a fleeting moment;” but the Pyramids, and ruins of Karnac survive the Kaliffs and Cæsars, the Ptolemies and Pharaohs, and countless monarchs and dynasties prior even to them. Thus, whatever learned disputants may imagine as to the primitive occupation of the valley of the Nile, the date of its occupancy, and the race by whom it was first cultivated, we have in the Pyramids incontestable proofs of a vast antiquity. Whatever historians may say of the antiquity of ancient Rome, the _Cloaca Maxima_ of Servius alone refutes the beautiful romance of Virgil--how Lavinius and Turnus received Æneas ere Rome was; how Romulus and Remus founded Rome, and were succeeded by seven kings, none of whom ever in reality existed. But the existence of the _Cloaca Maxima_ and the researches of the illustrious Niebuhr tell another tale more consonant with what we know of man’s social and physical nature. In the most remote times, man early adopted those measures of self-preservation which nature or simple observation teaches him. History gives but little information as to the measures adopted by ancient nations to secure public health; and were it not for the remains of the _Cloaca Maxima_, so called, of Servius Tullius, we should be as ignorant as Virgil assuredly was of the ancient condition of Rome prior to the reign of the seven fabulous kings.[58] Unquestionably the ancient race which preceded those grand Romans who fill the page of history for nearly twenty centuries, had discovered such means, and adopted measures for the safety of the people. Authentic history, it is true, commenced with the Greeks and Romans, and the history of Germany dates from Cæsar and Tacitus; but the subjugation of the double-horned Rhine[59] must have commenced long before “the building of the city.”[60] But the world as known to the Romans, even during the reign of Trajan, was a contracted world compared to what it is now. The tropical regions of the East, and their vast populations, were wholly unknown to them; of Africa they knew but little, of Asia still less, whilst the New World was as if it existed not. Thus certain great problems in the history of mankind were never presented to them, problems having a basis in facts which men, for obvious reasons, are so unwilling to admit. The periplus of the Mediterranean might almost be said to form the Roman world; beyond the Rhine they made no conquests; the Danube formed their north-eastern boundary; the eastern shores of the Black Sea were but rarely visited by them; beyond the Euphrates and Tigris they, the Romans, never gained a footing, whilst from tropical Africa they were entirely excluded. Thus at no time were they called on to solve the problem as to the possibility of European life maintaining its ground in tropical regions; at no period were they called upon to give an opinion on the momentous question which now agitates the world, the admission, namely, of the primitive coloured races of men into the bosom of civilized society.[61] “Wheresoever the Roman conquered, he inhabits;” a just observation we owe to Seneca, confirmed by the history of that wonderful people. As their conquests were confined to countries in which the natives of Italy could at that time live and thrive, the rapid extension of their empire, language, and forms of civilization, need not be wondered at. Thus Rome successively became mistress of many nations and races, but these were races with whom the Romans could freely amalgamate; at no period of her history were they called on to contend with the two great questions, the one social the other physical, involved in the attempt to occupy by a white race a tropical country, and a land inhabited by a purely savage race of coloured men; the problems presented by modern history of a European race attempting to hold India by the sword, to colonize the American world from the Polar Sea to the Land of Fire, to inhabit, if not to cultivate, the insalubrious Antilles, the banks of the Oronoco, or of the still more dreadful Senegal, Gambia, and Niger, nowhere occur in Roman or Grecian history; so that these are problems towards the solution of which ancient history offers no assistance.

[57] Gibbon.

[58] Niebuhr.

[59] Extremique hominum, Morini Rhenusque bicornis. _Æneid_ viii.

[60] “Ab urbe condita;” from the building of the city (Rome), the era
fixed on by the Romans.

[61] This question was first agitated in the reign of Justinian, on
the occasion of a proposal on his part to form a treaty with the
negroes of Abyssinia. But the Abyssinians were not negroes.

A historian whose works I have already quoted on several occasions, and who of all men had perhaps with most profit studied human nature, has remarked that the aspiring genius of Rome sacrificed vanity to ambition, deeming it more prudent to adopt virtue and merit for her own wheresoever they were found, among slaves or strangers, enemies or barbarians. This sacrifice it was easy for the Italian race to make; naturally swarthy, and not unfrequently olive-coloured, they met with no race with whom the Romans might not freely amalgamate. Far different is it with modern Europe and her races; follow them to tropical India, Africa, and America, and it will be seen that extinction seems the sure result of all their efforts, whether they unite with the native races or not. If they unite, their purer blood, as we may so call it, soon disappears in the stream of a darker population; if they spurn the union, climate, or as some would term it, malaria, speedily exterminates their race and name.

In the first or second chapter of this Essay I ventured to suggest that the discovery of the art to modify the earth, air, and waters of all countries, so as to render them habitable for _all mankind_, was the grand problem man is now called on to solve. In the construction of the continents of the globe, nature seems to have had in view the formation by centres of life of the living inhabitants of the globe. In these centres she placed forms of life equal to sustain their existence, occasionally aided, at other times unaided, by human industry. In the virgin forests of America the aborigines lived and throve; under their hands the earth underwent no modification; to the negro the deadly regions of Central Africa are healthful and pleasant, though at times abandoned to nature, at times deeply modified by human industry. India and Java, the Malayan peninsula, as well as ancient Mexico and China, were many of them highly cultivated regions, in which the aborigines multiplied and enjoyed life; to the European they are premature graves.

But when it is attempted to transfer these centres of life to other regions, the attempt has uniformly failed.

And yet the Romans, admitting that they never encountered a tropical climate, seem to have colonized and thriven in countries in which the natives of Western Europe cannot now maintain their ground, cannot keep an army effective in the field for any length of time. The Roman legions and citizens occupied the country of Numidia without an effort; modern France, with an army larger than Rome ever had, can scarcely maintain its position in Algeria. The young population are cut off in their infancy, and it would seem that to maintain a Celtic race in Algeria will test the energies of an empire which it is true formed but a small province of imperial Rome. When we contrast late history with the diffusion of Rome’s armies and citizens over the then known world, we are forced to the conclusion, either that the Italian constitutions of those days were stronger than those of the present inhabitants of Europe, or that the form of civilization presented more safeguards for the protection of health and life.

Nothing like the disasters of Varna and the Crimea seems ever to have overtaken the Roman legions who guarded in the time of Trajan the mouths of the Danube and the coasts of the Euxine, or restrained and kept in check the barbarous Moors.

Amongst the arts practised by the ancients, but now lost, we must include, I think, the knowledge of that discipline and practical skill by which the Roman, Greek, and even Tartar generals, contrived to keep their armies in the field in health and efficiency, whether storming the castles of Jugurtha, or building walls of defence in that land where English and French troops can neither fight nor march.[62] Amongst the lost arts, still known it would seem to the Chinese, is that of rendering salubrious the site of vast cities and camps. If I am right in the principles I have endeavoured to establish throughout this Essay, this art must have been based on the practical knowledge that, generally speaking, the earth, as framed by nature, is not usually an unhealthy _habitat_ for those races which grow up in her centres of created life, and it is only when man interferes, and interferes imperfectly, that the air and waters become pestilential to him. The secret lies, no doubt, in agriculture, that first of human arts--that art by which civilization exists. That human life is of as much value by the banks of the Meuse, the Scheldt, and the Rhine, as in Sussex or Surrey, is due to the industry of the inhabitants of Brabant and the islands of the Rhine. On man in a great measure depends the position which life is to hold in the scale of fate; he may raise it to its maximum or sink it to zero. Centuries, it is true, may elapse before human industry can render the banks of the Senegal, the Maranon, or the Zambeze, a fit abode for civilized European man, but if the European persist in transporting himself to these haunts, he must discover the means to do so in safety, or perish in the attempt. Nature did not make these countries for him, but she gave him reason, judgment, observation, and the power of generalization, on the right use of which faculties his safety must ever depend. The celebrated Jefferson apologizes in one his confidential dispatches to his government for noticing various political movements in countries seemingly remote from and devoid of all interest to a citizen of the United States of America, by remarking, that although such matters seem remote and foreign to the object of his duties, they may yet at no distant period swell into relations of sufficient magnitude to shake the world. As in the political, so in the moral world; whether the empire of the Sultans stand or fall, may be a matter of little import to an inhabitant of Western Europe, nor need it distress him that the finest countries in the world are nearly reduced to deserts under the administration of the odious Turcoman. But it may be useful to him to be on his guard as to the condition of countries through which the spirit of commerce now urges the Western nations. Many of these countries do not improve; to compare them with what they were in the days of Trajan were merely a mockery; the low lands of the delta of the Danube are simply foci of fever and pestilence, and are likely to continue so under their present government.

[62] Trajan’s wall, between the Danube and the Euxine, at Kostenjie.

All history points to the East and to Africa as the seat and source of plague, and the entanglement of Eastern affairs presses more and more on the European nations; if we may trust the statistics of commerce, Western Europe at times draws a large portion of her subsistence from countries of which we know but little. On this I make no remark, my object being merely to show that, however distant these lands lie, their malarious condition has an influence over the European family of nations, an influence which daily increases socially, and which, though originating in the obscure and unknown East, has shown itself at times at Rome and Moscow, London and Paris, in characters compared to which all other evils appear insignificant.

All that lives or has lived is doomed to die, to waste away, and to disappear; as it perishes it is consumed by nature’s processes, in such a manner as to entail no danger to the living world, unless civilized man interferes. For civilized man she has made no provision, saving the bestowing on him a soil more or less fertile, a constitution more or less equal to toil, a reasoning power, which in things practical must not be measured by the loftiness of his conceptions and generalizations.

Whenever and wheresoever he congregates into masses, there “the earth, the air, and the waters,” receive modifications from him, which, when injurious, he alone can rectify. The most consolatory view which man can take of such a condition of things is unquestionably to believe them to a great extent remediable by his own labour and intelligence; for even should he fail, there remains to him the consolation that he has done his best.

CONCLUDING CHAPTER.

AUTHOR’S THEORY OF MALARIA.

It is easier to pull down than to build up; easier to refute than to convince; easier to find fault than to suggest a remedy: and this reflection may occur, and no doubt has occurred, to those, be they few or many, who have perused the preceding chapters of this work. It may now be asked of me explicitly, What is your theory? What is your remedy for the evils complained of? To this I might reply, as the immortal historian of the “Decline and Fall” is said to have done, “If you have read certain chapters of my work with sufficient attention, you may extract from them my meaning and my views;” but as this might imply on my part either a Teutonic love for obscurity in phraseology, or a fear to commit myself to any theory, I shall here sum up in a few words the views I have arrived at after much reflection on the matter, during a long and active life passed in a country supposed to be a hotbed of malaria, the great source indeed of malaria in Western Europe, that land for which nature has done so little and man so much.

1. There floats in the lower strata of the atmosphere in all regions of the earth, but in very various proportions, for reasons already explained, a poison or poisons, generated by the processes which nature adopts for the destruction of past generations, and the reconstruction of those to come; the destruction of the aged, the worn-out, the nearly extinguished; the reconstruction of the organisms springing into life, to occupy the place of those that were! Whether the poison be one or many; whether it be a single species or one of a natural family, does not affect the general conclusions. The diversity of its effects is no proof of diversity in its essential nature or even origin; the living principle is supposed to be of one nature everywhere and for ever; yet see how varied are the results of this principle in moulding the vegetable and animal worlds; how slight are the modifications even in organic elements, which, when called into play, give rise to the most astonishing and unexpected diversity of results. Why should it not happen, then, with the poison, influence, or thing we call malaria, which, modified by a chemical action too subtle for the scientific man to observe, may yet, being so modified, give rise to an intermittent or a remittent, a plague, a cholera, a diphtherite, a scarlatina, a typhus, or a small-pox? Where did so many poisons come from? Whence came the murrains, the vine-plague, the potato-destroying poison, which was not at all new, neither was it confined to the potato? Whence came the pestilences which destroyed the ancient world? which exterminated at once whole species and genera now extinct? Of one thing we may be assured, they did not die a natural death.

2. This poison, whatever it may be, floats in the lower regions of the atmosphere, supported therein by the gaseous products of fermentation, and more especially by the ammonia now proved to exist everywhere in the atmosphere. It is the product, in fact, of the slow combustion perpetually going on in the air, the earth, the waters, wherever, in fact, animal or vegetable organisms are to be decomposed. We call it putrefaction; it is in truth a _ferment_, and the fermentable matter, that which gives rise to the ferment, is the immediate agent as well as the result (for it is the nature of all ferments to reproduce their process) of this fermentation, accumulated in the lower regions of the atmosphere. Increased to the dangerous point by men’s imprudence or ignorance, quickened by epidemic influences with whose nature we are of course wholly unacquainted, and absorbed by the living tissues, it excites that fermentation, that tendency to putrescence in the living blood to whose results medical men have given so many appellations. At times it is called ague; at times remittent fever; now it is small-pox; and now a fatal diphtherite. To the transit of _ferments_ through the air and to their inhalation by man, I ascribe the diseases usually called zymotic. In ancient primitive times, when physicians were rare,[63] and men did not interfere, a poison thus absorbed ran its course from incubation to specific fermentation, with all its results, in a given time, terminating in a crisis which might be calculated and determined; and which might prove fatal or at once remove the disease. A violent perspiration, a severe diarrhœa, a specific and contagious eruption on the surface of the body, proved and effected the elimination of the poison from the system. The ferment had done its work; it had altered the mass of the blood, and the products of the slow combustion (_putrescence_, rottenness, _fermentation_) were discharged by the secretions, according to circumstances peculiar to the constitution of the individual: as out of the same materials serpents elaborate poisons of very different powers and qualities, so the _ferment_, passing through various constitutions, gives rise to various results. It pervades the air and clings to it, nor can it be avoided but by a change of place of residence;[64] storms may, and no doubt do, affect it, but they frequently fail in dislodging the poison; intervening wide-spread oceans fail to interrupt its course;[65] and as regards the caprice exhibited in its attacks, we have only to reflect on the number of elements, vital, atmospheric, social, and chemical, involved in its full maturescence. Our doubts on all such matters originate probably in the coarse chemical theories and still coarser chemical experiments which prevailed about thirty years ago, and from their influence, from which men’s minds have not as yet escaped. The atmosphere was declared to contain a few wide-spread gaseous elements, and to be unalterable; the air of towns, of theatres, of large heated apartments, crowded with people, was boldly asserted by chemists still alive to be eudiometrically perfect.

[63] There were no medical men in Rome for the first five centuries
of her great career; and some have fancied that this fact explains
the astonishing number of armies which the republic found no
difficulty in sending into the field.

[64] When unassisted by other deleterious influences, the poison,
though all but universal over the locality, may not be destructive.
After the draining the Lake of Haarlem, the principal physician of
the district informed me that in 2000 cases of ague he had not lost a
patient.

[65] The choleraic ferment traversed in ships, no doubt, the
Atlantic, as typhus had often done before; but there are grounds for
believing that vegetable and animal matters in a state of rottenness
(fermentation), floating about in the air, are not unfrequently
transported to great and almost incredible distances. Ehrenberg and
Humboldt have particularly insisted on this fact, and have spoken of
distances traversed by these fermentable elements, which I hesitate
to quote from memory. Assuredly they were very great, extending to
some hundred miles from the seat of their origin.

§ 1. _Discovery of foreign bodies, the remains of animal and vegetable life, and therefore_ FERMENTABLE, _in the air floating over canals, ditches, marshes, &c._--Scientific chemists, as well as the professors of the conjectural art, are occasionally behind the knowledge of the careful, observing, unprejudiced practical men of the day.[66] Experience taught me, whilst engaged in other inquiries, that the sulphuretted hydrogen gas arising from the waters of the canals of Holland is quite sufficient to spoil cottons printed with nitrate of lead, used for dyeing yellow with the chromate of potass. The waters of these canals hold this gas in solution in a certain sense, but from May to September inclusive, the gas escapes during the night in great abundance.

[66] England has often paid a high price for the first steps in
science. Mr. Papillion, in 1806, received from Government 10,000_l._
for the introduction of dyeing Turkey red; and his success was owing
to his knowledge of the water proper for the operation, which must be
void of fermentable bodies.

At this time vapours arising from the waters and floating over the adjoining grounds, were found to contain minute portions of aquatic plants mingled with the spores of fungi in vast abundance, together with fragments of a membranous and gelatinous substance about to be mentioned. To these must be added the remains of infusoria not to be detected in dried specimens.

The injurious effects of water holding such substances, gaseous and solid, in solution, we overcome by boiling and passing the steam through (heated) iron pipes, and re-converting the steam into water. By this process we get rid of the injurious effects of these foreign matters, gaseous and solid, held in a kind of solution by the water, in as far, at least, as they affect the colours used in dyeing.

During these examinations of the waters themselves, it was distinctly observed that the infusoria and testaceous mollusca, microscopic and otherwise, with which such waters abound, were developed in glutinous membranes attached to the aquatic herbs abounding in these waters; in short, these membranes seem to be the matrix for the growth, nourishment, and production (using the term in a limited sense) of these organized beings; they form an essential condition of their existence.

The plants themselves were now washed in distilled water, and the animal products were the semivalve and bivalve shells of which I have preserved many specimens. The semivalve belong to the natural families Buccinum, Lynceus, Helix, and Planorbis; the bivalve to the Cardiacæ. The semivalves are the most abundant. By filtering the water which remained after the shells had been removed, innumerable minute particles like dust were discovered; these particles were ascertained by the aid of the microscope to be mainly composed of minute fragments of aquatic plants and of the spores of fungi; to these must, no doubt, be added, although not visible when dried, the remains of zoophytes, and of the glutinous membranes forming the matrix of animal aquatic life.

I now endeavoured to obtain the glutinous membrane or matrix in which these testaceous mollusca were obviously developed, apart and distinct from the animals themselves. To attain this desirable point we filled a glass receiver with water containing the aquatic plants and shells, and the gelatinous membrane already spoken of. The receiver was now inverted upon a plate, and water poured into the plate to the depth of half an inch.

In a few days the receiver became filled with gas, forcing the water downwards into the plate on which the receiver rested; and although after the first day we could not discover any of the gelatinous membranes in the lower part of the receiver, yet that in the plate became like a flaky jelly, attaching itself to blades of grass or leaves. The surface exposed to the atmosphere became dry and brittle, and in this state resembled thin layers of gum; the substance thus desiccated strongly resembled jelly.

The glutinous membrane of which frequent mention has been made above, is of a very viscid nature, and when combined with any animal substance in a state of transition or fermentation, it is poisonous. It is, I believe, generally viewed as the matrix for the development of the ova of these shell fish, and considered as a product or secretion of the parent. Into this question I enter not, leaving it, if it be one, to others.

On exposing for a few days some of the larger testaceous mollusca alive to the atmosphere of the room at a temperature varying from 65° to 70° Fahr., strong proofs were obtained that ammonia was produced in the interior of the shell confined therein by the membrane called operculum, sealing, as it were, the aperture into the shell hermetically. On puncturing this membrane the presence of ammoniacal gas could be distinctly traced by the odour.

I submit to the consideration of professed physiologists the following questions:--1st. What are the effects likely to result to man from the inhalation of these microscopic and gaseous products in a state of decomposition, they being certainly present in the vapours arising from the waters of canals, ditches, &c., in many countries, especially during the nights of spring, summer, and autumn? 2nd. What are the evil effects likely to arise to man from the use of such waters as drink, or when employed for culinary purposes? Lastly: As the gelatinous membranes alluded to are the nidus of various forms of organic life, and contain those forms, developed and undeveloped, occasionally in a state of decomposition, to which of the two forms of life, animal or vegetable, or to both, is to be ascribed the deleterious effects on man, and ascribed by physicians to an unknown poison called Malaria, designated by them as “a poison, an influence, a miasm, a thing unknown”? Ferments and putrescence are not “things unknown:” let us adhere to facts.

§ 2. Thus the principle of wasting away by the action of the atmosphere, of the rotting of vegetable and animal substances, first developed by the illustrious Liebig, opened up to me the path to that theory which seems to reconcile the conflicting observations of pathologists,--that vegetable and animal matters do ferment or rot, and that in this state of rottenness they are carried through the air, was with me no longer a matter of doubt; next came the question, as to the effects of such matters on man when inhaled by respiration and conveyed directly into the living, circulating blood, that most complex of all fluids, that mysterious compound out of which nature constructs the animal world.

This slow wasting takes place in any damp place under ground, and the ferments assume the form of vapour when such places happen to be warmer than the open air; it is in this state that the odour is so sensible to us after a hot dry day or during cold nights. There is no smell in rainy or damp weather. It is in the spring and autumn months when ferments from slow combustion abound, aided by the amount of heat and moisture which then prevail, and by the floating of plants. The poison thus generated is known to be the product of a ferment, and like many such products, possesses the quality of fermenting other organic compounds with which it may come in contact. Introduced into the living system of man, it finds in certain individuals the material already disposed to pass into fermentation. It incubates, and this incubation is measured as to time by a variety of circumstances I need not enumerate. In cold countries the incubation is slow, extending over many months; not that the ferment differs, but its action is modified by the existing condition of the accessories to its action and power. The ferment introduced into the blood in autumn may not show its full action on the living fluids until the following spring, or early in summer: in hot countries it is different; there the ferment, aided by numerous adjuncts, acts almost immediately; fever sets in, causing violent reaction of the conservative powers of nature; delirium, coma, vomiting, death. The mass of the blood has undergone a change in all its constituents, and dissolution and putrefaction are swift in reducing the frame, even whilst life is still present, to that state to which all that lives must come at last; whilst the physician loses himself in vague theories of an “unknown poison”--a malaria, a something not strictly a gas, a matter or influence differing from all chemical or other agents known, the scientific chemist steps in, and shows that the subtle matter they so anxiously endeavour to discover, is a process constantly going on before their eyes; a chemical process, universal; the process, in short, on which in a great measure depends the disposal of the dead and effete remains of the organic world; the growth, the nourishment, the renovator of each successive generation of the same world.

§ 3. It may be now fully admitted that ammonia is the active principle or stimulus to vegetable life, as shown by the extraordinary growth of plants in warm damp climates; in these malaria--as we may still call the poison so developed--exists to the greatest extent, as in the Pontine Marshes, by the banks of the Po, Ferrara and Bologna. From various experiments and observations, I have been led to the conclusion that the ammonia constantly present in the atmosphere, and derived from several sources,[67] is the chief cause of the activity which the ferment, or poison, displays under different and varying circumstances. There prevails, in truth, an excess of ammonia in such an atmosphere, resulting from the nitrogen uniting with hydrogen; from the decomposition of vegetable matter carrying decayed animal matter along with it; and from the ammonia always existing in the spawn and in the matter of the shells of infusoria. All my researches into the effects which the various gases have upon animal tissues, showed ammonia to be the most destructive; in fact, no animal tissue can resist complete decomposition by caustic ammonia. I conclude, therefore, that vegetable and animal matter in a state of fermentation, and mixed with ammonia, is the cause or essence of that destructive power which physicians ascribe to malaria. Should this fermentable matter pass in a concentrated state into the torrent of the circulation, the globules of the blood are destroyed, and become black; the person is in the cold stage of fever; next, the vegetable matter ferments, causing the hot stage. No one in Holland has any doubt as to the origin of this power, but ascribes it uniformly to the draining of some lake; and it amounts almost to a demonstration that the air under such circumstances is poisonous or injurious to health. It was even foretold by several writers that fevers would result from draining the lake of Haarlem, as took place in the years 1608, 1641, 1727, 1779, from draining various polders.[68]

[67] The ammonia always present in the atmosphere is probably derived
chiefly from the union of nitrogen and hydrogen; but much of it also
no doubt has its source in the fermentation of animal and vegetable
remains.

[68] Baron von Lynden.

If the principles I have announced be correct, the extreme impropriety--not to use a stronger phrase--of carrying on excavations or other extensive works on the muddy banks of rivers, in marshy or swampy forests, during the summer months, must be obvious to all reflecting persons. No work should be done in such places, or in ponds, after the month of April, for it is warm dry weather that sets malaria afloat. But if this ferment--which we may strictly call malaria, as producing a malarious condition of the air--be, as I apprehend it is, the cause of fever, why should not medical men direct their attention more earnestly to the question in how far such a fermentation of the blood may be met by the employment of substances known to resist and counteract fermentation? Are physicians agreed on the nature of fevers, and the best means of curing them?[69]

[69] I have known many persons sickly from the effects of
intermitting fever or malaria from a residence in warm climates,
and who have suffered and perished from an injudicious treatment.
Ill-formed or incomplete agues are extremely common, even in the
south of England, in London especially. They show themselves under a
variety of forms, and with much severity, in the cases of those who,
having once visited a true malarious climate, are ever afterwards
more or less liable to a return of the disease. Let men reflect;
simple truths travel slowly, yet are truths notwithstanding. The
death of the well-known M. Soyer was evidently caused by his wholly
misunderstanding the nature of his complaint, which, in fact, was a
fever originally caught in the Crimea.

Nothing can be more interesting, in a natural history point of view, than to watch the results upon large bodies of water, of attempts, more or less successful, to complete their drainage. Thus during the operations carried on for this purpose at Haarlem, there sprung up in the dry places of the more elevated parts an extraordinary quantity of plants and herbs, which were not seen in the country before they flowered and sent millions of seeds with their diminutive rocket, silky tails into the air. They were too minute to be seen upon grass, but the footpaths were covered with them, and a current of wind might carry them to distant regions, as the sand is carried from the coast of Africa into the track of the Brazilian packets, to such an extent as to make it uncomfortable to walk on deck. It is by no means, therefore, improbable that those errant seeds came from a foreign land, the native produce of other countries. Continuing my observations into the transit of seeds, I have found them to be the cause of shallow canals in England being full of heretofore unknown water-plants, to the extent of impeding navigation.

It is mentioned in the “Kosmos” of Humboldt, that the dust resulting from eruptions of the volcanic mountains in South America was observed in Spain. But if currents of wind thus carry seeds and other matters hundreds of miles through the air, no one can be surprised that the aquatic plants above alluded to floated to England through the air, from Holland; these plants, new to the land of their accidental adoption, bring with them a new corresponding animal life; in due time they come to maturity and die, and now Nature steps in to take up the task, and complete her work; her process is simple in appearance, most complex in its results: a malarious air--malarious at least to man--appears, as it may be, for the first time in the district, ascribed by medical men to every cause but the true one. In their anxiety to discover a cause, they fix on some antiquated drain, or cesspool, or ditch, by the margins of which many generations of a stout peasantry had lived and died; or they dive into the pump-well, and triumphantly exhibit infusoria, not unlikely engaged at the very moment in purifying the water: it never seems to have occurred to them that _ferments_ only appear in certain combinations of the air--under circumstances which only occasionally occur, and that (which is most lamentable to think of, as in the case of London and the Thames) the evil is most frequently of man’s creation.[70]

[70] A friend who resided long on the Grotevisch Rivière, and in het
land den Caffre, informs me that if the Zuureveld be ploughed up, or
altered by the burning, for example, of a Caffre hut, the sour grass,
whence the district derives its name, disappears, and sweet herbage
of various kinds take its place. None of these exist naturally in the
district, so that the seeds must come from great distances.

The operations of nature when left to herself never vary; they may always be calculated on, foretold, anticipated; on this assured and irrefutable fact all science rests. It is only when man interferes and modifies the elements at work that nature seems to alter her processes; a disturbing agent has been thrust into the machinery, and the mischief it effects must either be counteracted or entirely overcome. So long as the Lake of Haarlem was a lake, or mere, so long were its banks healthy; but drain it partially, and you must be prepared for the result. There is no middle course; that which was once a lake or sea cannot be left in the condition of a putrid, imperfectly-drained, fermenting mass of mud, teeming with animal and vegetable life, and with a material for which oxygen is the natural ferment; it must be arrested by the hands which drained, or attempted to drain it, and converted into a healthy pasture-land or a wheat-field; if left to nature, centuries might elapse before that which was once a sea would become a healthy forest or natural meadow, during which period man, should he persist in residing on its banks, must undergo the penalty of his own want of knowledge.[71]

[71] The effects of partial and incomplete drainage have ever been
the same. In 1823, when the new Polder was made at Neusen-on-the
Sheldt, small-pox raged in the neighbouring villages to such an
extent that the children were forbidden to attend school. The effects
are to be seen now in persons over sixty years of age, bearing the
marks of the epidemic. The whole atmosphere of the district was
infected.