PATHOLOGY. 
Ful ravages on mankind, and concerning the origin of 
which the medical world is much divided. The conflift- 
ing opinions of medical men on this fubjeft are indeed 
well known to the public ; the grand quelfion to decide 
being whether yellow fever is contagious or not. It is by 
no means eafy however to trace the operation of the in- 
fcrutable agents which give rife to this difeafe: and hence, 
while one phyfician attributes its diffufion to exhalations 
from the body of the human fpecies, another finds per¬ 
haps in the fame cafe evidence of its origin from miaf- 
mata. In a late number of the Medical Repofitory we 
find the names of numerous and refpeflable authors mar- 
fhalled in regular array againft each other as taking oppo- 
fite fides in this important queftion, We copy the chief 
of thefe, that thofe who want to examine cloftly the evi¬ 
dence on each fide may have recourfe to it. 
Among thofe who confider yellow fever to be an im¬ 
ported and contagious difeafe, are ranked Arejula, Batt, 
Berthe, Dalmas, fir J. Fellowes, Moreau de Jonnes, B. 
Progetto, Salgado, &c. who found their opinions on the 
yellow fever of Spain; and more recently Parifet holds 
the fame opinion. Alfo Bally, fir Gilbert Blane, Cai- 
zerques, Chifholm, W. Currie, Des Portes, D’Oyarvide, 
Lind, Ried, &c. who derive their fatlfts from the Weft 
Indies and America. 
Among thofe who deny that yellow fever is conta¬ 
gious, and afl'ert its origin to be entirely local, or depen¬ 
dent upon fome myfterious and inappreciable change in 
the atmofphere, are ranked Amiel, Burnett, Caftan, 
Doughty, Keutfch, Lacofte, Langerman, O’Hallaran, 
See. who draw their obfervations chiefly from the fever of 
Spain ; and Bancroft, Barker, Browne, Comftock, Clarke, 
Coventry, Davidge, Denmark, Deveze, Dickfon, Fer- 
gufon, Gilbert, Hillary, J. Hunter, R. Jackfon, Jeft'er- 
fon, M'Artlnir, M‘Lean, E. Millar, Moore, Mofeiy. Muf- 
grave, Mnttlebury, Ramfay, A. Robertfon, B. Rndi, Sa- 
varefi, Selden, Sheppard*Trotter, Valentin, Vanel, Veitch, 
Whitehead, &c. in the Weft Indies and America; and 
in Africa, Drs. Copland and Winterbottom. 
Among thofe who hold a middle courfe, allowing the 
local origin of the fever, but afferting that it may be¬ 
come contagious, we find Eytnann, Hofack, Humbolt, 
J. Johnfon, Le Blond, Nicol, Palloni, Pugnet, Romans, 
‘ Sec . 
To thefe we mull add the Angular opinions of Baron 
Larrey. This author divides virus into two kinds ; the 
one fluid, as in fiphilis, fmall-pox, and vaccina; the 
other gafeous, or miafmatici of this laft fort is (he fays) 
the virus of the yellow fever. Each virus has a particu¬ 
lar influence on certain parts. That of the yellow fever 
adds particularly on the nervous fyftem of animal and or¬ 
ganic life. It is connedded with the lymphatic fyftem ; 
and, according to him, it is the moft fubtle and fuga¬ 
cious of all. It lafts but a moment at the higheft point 
of difeafe; and then lofes the power of tranfmitting it- 
l’elf. It is principally feated in the exanthema when this 
exifts, and in the cutaneous tranfpiration. It is in this 
manner that M. Larrey endeavours to reconcile the con- 
tradi&ory opinion of phyfleians on this fubjeft. He is, 
however, an advocate for meafures of precaution ; for if, 
lays he, one patient only out of a hundred lie capable of 
tranfmitting the difeafe, prudence requires that the whole 
Ihould be fequeftered, as it is impoflible to afeertain the 
individual by whom the difeafemay be perpetuated. 
For our own parts, we can only give the ccnclulions 
we have arrived at from an attentive perufal of moft of 
the above w'orks. It would far exceed our limits to de¬ 
tail, even in the moft comprefted form, the arguments of 
thefe numerous and confliffing authorities. But, taking 
up thofe opinions which feem to have been moft carefully 
induced from fadis, and which in fome manner explain 
ffte diftonant evidences of various authors, the follow¬ 
ing circumftances appear to us tolerably well eftablifhed. 
Firftthat the yellow fever, the bilious remittent, the 
Bengal fever, the liulam fever, See. are all one and the 
VOL. XIX. No. 1258. 
215 
fame difeafe modified by varieties in climate, conftitution, 
and predifpofing caufes; that is to fay, that they are fo 
far the fame difeafe, that their fundamental therapeuti¬ 
cal indications are fimilar, and that they are apt, when 
external circumftances ferve, to run into each other. 
Secondly, that this fever is for the moft part caufed by 
certain miafmata from marfhy foils, which miafmata are 
fuppofed to be the prodmft of putrefying vegetable fub- 
ftances, it being urged that animal putrefaction is not 
found to produce yellow fever. This, however,is by no 
means clearly afeertained. It is afferted that the mial- 
mata in queftion are generated for the moft part in fixa¬ 
tions where the water has receded or been partially dried 
up, and where confequently the muddy bottom is ex¬ 
posed to the fun’s rays. It is afterted alfo, that an high 
temperature is an indifpenfible condition to the produc¬ 
tion of thefe miafmata, or at leaftto their morbid aftion 
on the human body ; whether fuch heat be in aftual ex- 
iftence,or whether it has immediately preceded a fudden 
acceftion of cool weather. 
Though thefe miafmata from marfliy foils are undoubt¬ 
edly in many inftances the foie caufe of the yellow fever, 
yet fomething mull be often attributed to the influence 
of defeending dews from the atmofphere. Indeed Dr. 
James Johnfon mentions having himfelf experienced the 
ienfible eft’edl of this dew on-board of a (hip; and it 
feems very probable that jt was only by the preventive 
treatment he employed, that he warded off an attack ot 
this fever. This author likewife informs us, that a fever 
which broke out in the Leopard’s crew followed upon 
a defeent of dew which took place every night, and 
was perfectlyJalt and litter to the tojle. The above-men¬ 
tioned fad, according to Dr. J. Johnfon, leads to a 
“ praftical inference of confiderable utility; viz. that, 
when neceftity compels us to penetrate through thofe in- 
falubrious woods, jungles, or marlhes, we fhould feleCt 
that point of time at which ive are lead likely to meet 
thofe miafrns, whether in their afeending or defeending 
ftate. This period feems to extend from three to fix 
o’clock in the afternoon ; that is, after the greateft heat 
of the earth and air, and, confequently, the greateft eva¬ 
poration ; and before the condenfation and return of 
fuch exhalations as rofe during the day, and which 
combine with thofe ftill iffuing from the heated foil 
for fome time after fun-fet. Independently of this cir- 
cumftance, the body feems to be pofleffed of greater 
energy at this period of the day than at any other, it 
being that time when the principal meal is nearly di- 
gefted, and confequently the animal vigour at its higheft 
pitch. The deprefling paflions, intemperate or bad liv¬ 
ing, and the other predifpofing caufes of the fever of this 
country, aCt with equal or greater force in aflifting the 
baneful operation of the mialms of yellow fever. 
Thirdly, it is inferred as a probability, (for we have 
no evidence of our own to offer,) that yellow fever ari- 
fing from miafmata may in fome conftitutions generate 
the volatile material which other fevers do, and produce 
contagion. Independently of the evidence derived from 
the authors before mentioned, the principles we have 
laid down when treating of contagion lead to the fame 
conciufion. Indeed, when we confider the nature of 
contagion itfelf, we cannot refufe ouraffent to the propo- 
fition in queftion. We fee that a fever, clearly traced 
in the firft inftance to local injury, will, under the con¬ 
comitant circumftances of foul wards in an hofpital, 
deficient ventilation, &c. engender contagious fever 
through large bodies of men ; fo that we infer that any 
fever, however induced, may be contagious, feeing that 
its local origin does not hinder the contagions effluvia 
from being produced. Moreover, let us confider the 
manner in which contagion is produced. Itmuftbearo- 
lalilefecretion; and this can only arife from the mucous 
membrane. Now, when we fee the great variety of ap¬ 
pearances-which the vifible produdfts of this membrane 
exhibit when inflamed, can we doubt that in almoft ail 
3 K violent 
