l AGUE. 



time, and consequently the paroxysm occtin every day. ThU (urm of 

 ague U distinguished from the quotidian, by comparing the paroxysms 

 with each other. Though a paroxysm occur every day, yt if they be 

 carefully observed it will be found that the alternate paroxysms only 

 resemble each other, while if the paroxyim of a preceding day be com- 

 pared with that of a succeeding day, some manifest difference will bo 

 observable. There may also be another form of the double tertian ; 

 namely, with two paroxysms on one day, and another on the following 

 day ; or there may be a triple tertian, with two paroxysms on each 

 alternate day, and one only in the intervals. The double quartan also 

 varies. It may occur with two paroxysms on the first day, none on 

 the second or third, two again on the fourth day, or with a paroxysm 

 on the first day, another on the second, but none on the third. 



But whatever be the form of fever, the nature of it U essentially the 

 same : yet the form is of some consequence, as denoting the severity 

 and tendency of the disease ; for a quartan is far more obstinate than a 

 tertian, while k quotidian is apt to change into a continued fever. 

 Quartans, for the most port, appear in autumn, while tertians are the 

 most common in spring. 



Whatever be the form of fever, the duration of the paroxysm is different 

 in almost every different case. The longer the paroxysm, the shorter 

 the intermission ; the shorter the intermission, the longer the paroxysm. 

 An extension of the period of the intermission, or a postponement of 

 the period of attack, is in general a favourable event, denoting that the 

 disease U declining ; on the contrary, a prolongation of the paroxysm, 

 or an anticipation of the period of attack, marks an increase in the 

 severity of the disease, and is a sign that the intermittent U about to 

 lapse into a remittent or into a continued fever. 



From the preceding history of the disease it is clear, that tin- dis- 

 tinguishing character of intermittent fever ia the regular return of the 

 paroxysm at a fixed period, the entire cessation of it after a certain 

 time, and the renewal of it after a specific interval, according to the 

 species of the ague. Nevertheless, though these distinct intermissions 

 and accessions are always apparent when the ague is regular, yet in the 

 most severe and formidable cases it entirely loses its intermittent 

 character and assumes a remittent, or even a continued form. 



Cases which ore frequently considered and treated as continued 

 fevers, are often of the nature* of intermittent. If a fever, truly of an 

 intermittent nature, be of a bad kind, it often commences with the 

 fonn of on alarming and dangerous continued fever ; but as the disease 

 declines and becomes milder, the intermission becomes apparent, suul 

 the true nature of the malady manifest; while, if an intermittent c.mi 

 raences under its own form, but in its progress becomes severe, it often 

 changes into a disease which cannot be distinguished from a con- 

 tinued fever. 



There is nothing in the nature of disease more curious and inexplica- 

 ble than this property of periodicity. During the intermission what 

 becomes of the malady ? Why after a specific interval docs it uni- 

 formly recur ? Physicians have endeavoured to refer this singular 

 phenomenon, which, if it were not so clearly seen would not be credible, 

 to the principle of habit ; but this really affords no explanation, and in 

 fact we have not advanced a single step towards the elucidation of 

 these questions beyond the jioint at which Sydeuliam left them 

 200 years ago. 



K.rcilig Vaiuc of Ayue. That the effluvia which arise from stagnant 

 water or marshy ground, are the immediate or the exciting cause of 

 this disease, is now universally admitted. What the nature of these 

 effluvia is, is not known. Neither their physical nor their chemical 

 properties have been ascertained. Kven their presence is known only 

 by their effects on the human constitution. No other test of their 

 existence has as yet been ascertained. The most distinguished chemists 

 have applied all the resources of their art to the investigation <>f this 

 Hiibject, but hitherto with so little success, that all which they have 

 ascertained is the mere fact, that in certain situations an :. 

 substance is generated capable of producing intermittent, remittent, and 

 continued fever, together with several other painful and dangerous 



AOUB. 



II 



Though this poison be generated in the greatest abundance and 

 intensity in marshy and swampy ground, yet without doubt it is also 

 produced in situations which have none of the characters of a marsh. 

 Wherever the ground is moist and contains decaying vegetable matter, 

 this poison is capable of being generated. Woods afford it in almost 

 as large a quantity as marshes, because in woods the ground remains a 

 long time damp, and always abounds with decaying vegetable matter. 

 Hence in all the densely wooded part* of England both intermittent 

 and remittent fevers are rife. This is especially the case in the 

 woody districts of Kent, Sussex, Hampshire, Wales, Ac. The jungle 

 of India consist* of a low and dense brushwood, or a thicket of reeds 

 and grass ; and intense heat acting on the wet and decaying vegetation 

 with which it abounds, the poison is here produced in the highest 

 degree of concentration. Rice grounds, for the same reason, are 

 notoriously productive of it But it is curious that the clearing of 

 woods sometimes increases t the evil. Dr. Rush states that, in Penn- 

 sylvania, epidemics invariably follow the clearing and cultivation of 

 forest lands, and that they do not disappear until after many yean of 

 continued cultivation. The same remark has been mode in France; 

 and the di-itnct t I'r.-.-c i l.yoniiais), which was comparatively healthy 

 v hen full of wood*, luw become nearly depopulated since tin v , 



down. The shade of the trees keeps the sun to a great exteir 

 the wet ground ; but the removal of the trees exposes the 

 U> the full action of the sun. Meadow loud, imperfectly drained, 

 contains in abundance the two condition-, , ., . -,irc and decaying 

 vegetable matter, and is in England a frequent and extended source of 

 ~m. It is commonly considered that a Urge space of land in 

 lition of a marsh, a swamp, a thick and damp wood, 

 undroiued meadow, is necessary to the production of the 

 while it is not easy to fix the minimum of the space that is n- , 

 it is quite certain that an exceedingly small space is sufficient. 

 facts show, in a striking manner, the danger and foll\ 

 artificial marshes as ornaments in parks and gardens. 



Wherever generated, this poison, either mechanically iniv 

 chemically combined in the air, is capable of being conveyed in 

 nn ini | aired power to a considerable distance by currents of wind' 

 influence of the Pontine marshes, situated at the distance 

 miles from Rome, is often felt in that city. 



In warm climates where this poison is generated in the highest 

 degree of intensity, it sometimes proves suddenly fatal to indivi.l 

 a ship's rrcw when the vessel is several miles from land. It is Li 

 with the land-wind. It seems certain that the poison can be carried as 

 for as the smell of the land is perceptible. A memorable instance of 

 this occurred in a vessel that .L- five miles from shore. Tin- wind 

 suddenly shifted ; the smell of laud was perceptible ; the nature of the 

 neighbouring coast was known to the people on board, and the danger 

 duly appreciated ; every one that could do so hasten, i l.rl,.w to save 

 himself from the noxious breeze. Some of the crew h, 

 unavoidably employed on deck ; the armourer of the ship was <!< 

 a few minutes in order to clear an obstruction in the chain cable, and 

 was seized with fatal cholera in the very act in which he was engaged. 

 Of the men that remained on deck, several died of the some disease in 

 a few hours, the attack having been simultaneous with the very first 

 perception of the land smell ; and in our country it i.- often c. > 

 by currents of wind to a distance of several miles. !\- j',i,,. 



oeeds to the hills of Kent, for example, several miles distant from the 

 marshes of Krith, Northfleet, or Qravesend. Tin- watery \u|> 

 is so apt to arise in situations most favourable to the genet 

 poison, appears to be an exceedingly formidable conductor of it. Sir 

 John 1'ringle, who had many opportunities of observing this fact in the 

 campaigns in Flanders, about the middle of the i , , uni- 



formly found that the number of men who \ ; witl, 



sickness during the prevalence of a fog, far exceeded the n 

 attacked when the weather was clear, though he did not attrii 

 the fog the production of the poison, but justly considered it as i 

 the conductor of it. 



There are spots in which this poison is generated in such quantity 

 and intensity, as to be capable of killing instantaneously wh. . 

 exposed to it. Exposure to it in certain situations boa ]>io\, 

 with a rapidity and certainty equalled only by a mortal dose of Prussio 

 acid. Exposure to it in other situations produces what appears 

 and what is sometimes mistaken for, apoplexy an affection of th,. 

 brain, causing death more rapidly than almost any other disease to 

 which the human body is subject. Exposure to it when less concen- 

 trated produces malignant fever of a continued form, destroying life in 

 a few days or hours. Exposure to a still smaller concentration pn, 

 duces remittent, and to a yet smaller, the milder form of inU-rt 

 (MT. Anil it liny be so minute in quantity or so destitute of MI 

 in its own nature, as to be incajiable of producing r\m int, n 

 fever, in its regular and well-marked form, and yet siifflcienth 

 to produce a long catalogue of grievous maladies. The sec, 

 diseases which have this origin, and which have been much overl. 

 consist for the most port of those painful affections of the nerves, which 

 have been lately classed together under the general term of nt. 

 [NBURAIXIIA.] The exquisitely painful, and too often unmanageable 

 diseases called tie douloureux, the disease called sciatica JJic toothache, 

 and more especially periodical headache, ore oftentimes clearly traceable 

 to this poison, and are as certainly produced by it as the most distinct 

 and regular ague. Persons who live in situations where this p.> 

 generated in abundance may never have ague, but at the san 

 they never enjoy a moment's health; while it is certain that long- 

 continued exposure to it, though it may not produce any i-> 

 disease, included in the catalogue of the nosologist, fi-.n fidlv :>' 

 the term of life. Few persons in such situations attain the age of 

 fifty. In some parts of America few of the inhabitai 

 beyond the age of fmty : those who survived thus long had. '.< 

 early {>eriod, all the characters of extreme old age. Already, in those 

 very situations, by the clearing, draining, and general rultiva' 

 I. the average term of life has been extended fifteen < 

 twenty years. There can be no question that the value of life whirh 

 in modem times lias increased so much in our own country, and which 

 has improved in the rural districts in proportion to the better culti- 

 vation and the more complete draining of the land ; and in the larger 

 towns and cities to the better ventilation and the greater cleanliness for 

 which they have been remarkable, bos been mainly owing to these 

 causes. 80 recently as the beginning of the present century, a cele- 

 brated physician, who had large experience of this i ,, as a 

 fact that came within his own observation and experience, that in 

 small villages, in which the iiiiiiml nni.il .. Hacked 



