PATHOLOGY. 
y. Perioftii, the malignant whitlow, or felon : effufion 
feated between the periofteum and the bone, which is of¬ 
ten rendered carious. 
Similar inflammations are occafionally to be found in 
the foies of the feet and palms of the hands ; they break 
through the cuticle with difficulty from its thicknefs, 
and hence become diffufed, and feparate the cuticle from 
the flcin beneath. The bite or poifon of the Gordius 
aquaticus, or hair-worm, is laid to have a pecular ten¬ 
dency to produce this affedion. 
Genus VI. Erythema, [Gr. from spsv&oq, rednefs.] In¬ 
flammatory fluff), improperly called Eryfipelas. Generic 
characters—Red, glabrous, tumid, fulnefs of the inte¬ 
guments; difappearing on preflure ; pain burning ; in¬ 
flammation ulcerative ; terminating in cuticular fcales 
or veficles, occafionally in gangrene. There are fix 
fpecies. 
1. Erythema adematofum, cedematous inflammation: 
colour fcarlet ; threading widely and deeply through the 
cellular membrane, which often imperfedly fuppurates, 
fioughs, and becomes gangrenous. 
2. Erythema eryfipelatofum, eryfipelatous inflamma¬ 
tion : colour deepi(h-red ; fuperficial; with a determined 
edge; migrating in a Terpentine direction; the part 
which has pafled through the aCtion healing, as the part 
next attacked becomes aflfeded. 
3. Erythema gangraenofum, gangrenous inflammation : 
colour dulky-red ; fuperficial ; cuticle feparated from 
the cutis by a bloody ferutn ; the cutis, when denuded, 
exhibiting dark-brown fpots, difpofed to bliffer and 
flough ; occurring chiefly r in the extremities. 
Thefe three fpecies are ufually to be found in debili¬ 
tated or relaxed conftitutions : the former two often ap¬ 
pear as fequels of atonic fevers ; the third is common 
to old age, and early infancy. For the treatment, fee the 
article Surgery. 
4. Erythema veficulare, fiery inflammation : colour 
pale-red ; furface roughilh, and covered with crowding 
minute veficles, filled with an acrid, often a reddifti, 
fluid ; progreflively trailing into the neighbouring found 
parts. 
This is intended, as Dr. Good informs us, to deline¬ 
ate the ignisfiacer of the ancients, which has been feldom 
underftood, and never hitherto allotted a clear methodic 
pofition. The common error has been in making it an 
exanthem, or eruptive fever, an Eryfipelas or a Peffis, 
or a diftind difeafe approaching to the one or the other. 
There is no doubt that it has at times been an accompa¬ 
nying fymptom in Pettis, and has confequently produced 
a variety in this fever which the reader will find noticed 
under the head Pettis by the diltinguiffiing term erythe- 
Kiatica, of which nature was the plague of Athens, fo 
excellently defcribed by Thucydides and Lucretius. 
But the ignis facer, in its genuine and fimple ltate, in- 
ltead of being a typhous eruptive fever, has often very 
little fever of any kind, never perhaps more than fymp- 
tomatic fever; and by Celfus is defcribed as being bed 
cured by an ephemeral or other fever that may give in- 
creafed adion to the fyttem. The varieties are, 
a.. Benignum : the rednefs and veficles advancing 
without a breach of the cuticle, as the part that has 
pafled through the adion is healing. 
/ 3 . Corrofivum : the veficles breaking in the part firft 
aft’eded, and theerofive fluid producing tracks of fanious 
ulceration as the rednefs advances. 
Thefe fubdiviiions of ignis facer are taken from Cel¬ 
ias, and given, as nearly as may be, in his own words, 
to prevent all doubt. Fie defcribes it as a genus compri- 
iing two fpecies, of which the former has two varieties. 
“ Dus fpecies funt. Alterum eft fubrubicundum, aut 
mijlv.ni ruborc atque pallore, exafperatumque' per pvfiulas 
(OAvxTKim?) continuas , quarum nulla altera major eft, 
fed plurimee perexigutx, In his feinper fere pus, et ftepe 
rubor cum calure eft.” Then follow the two varieties as 
defcribed above : “ a, Scrpilque id nonnunquum fanefeente 
eo, quod primum vitiatum eft ; Q, nonnunquam etiam ex- 
ulcerato, ubi ruptis pujlulis (<p\vy,’ru,ivu.iC) ulcus continu- 
atur, humorque exit." Fie then pafl'es on to deferibe the 
fecond fpecies, which anfwers to the character and al- 
moft to the words of our third fpecies, Erythema gan- 
grtenofum. “ Alterum, autem, in fiumvus cutis exulcera- 
tione, fed fine alliludine, latum, fiublividum, inasqualiter 
tainen 5 mediumque fanefeit, extremis procedentibus ; 
ac ftepe id, quod jam fanum videbatur, iterum exulcera- 
tur : at circa, proxima cutis, quae vitium receptura eft, 
tumidior et durior eft, coloremque habet ex rubro fub- 
nigrum. Atque hoc quoque malo—in cruribus maxime." 
Lib. V. cap. xxviii. fed. 4. 
Dr. Good has ventured to tranfiate the pvfiula of Cel¬ 
fus in the prefent inftance tp^oy.xa.ivxi, veficles ; firft, be- 
caufe he thus explains the term in fed. 15 of the fame 
chapter; and fecondly, becaufe in the ignis facer, which, 
as we learn both from Thucydides and Lucretius, was a 
fymptom in the plague of Athens, the former has given 
us this precife term. The following couplet is fufficient 
from Lucretius. De Rer. Nat. vi. 1164. 
Et jimul, ulceribus quafii invjlis, omne rubere 
Corpus, ut ejl, per membra facer quum diditur ignis. 
Wide ting’d with purple dye, and brandifli’d o’er 
With trails of caultic ulcers, like the blaze 
Strew’d by the holy fire. 
In Thucydides the fame fymptoms are defcribed ; and in 
Seneca, who has clofely copied from Lucretius, the phrafe 
facer ignis is ftill preferved. See CEdip. 187. 
The Eczema rubrum of Dr. Bateman feems to belong 
to this fpecies, and may form a third variety. It is com¬ 
monly denominated Erythema mercuriale or hydrargy¬ 
ria. This difeafe is preceded by a fenfe of ftiftnefs, 
burning heat, and itching, on the part where it com¬ 
mences, Which is moft frequently the upper and inner 
furface of the thighs, and about the ferotum in men; but 
fometimes it appears firft in the groins, axillae, or in the 
bend of the arms, or about the wrifts and hands, or in 
the neck. Thefe fenfations are foon followed by an ap¬ 
pearance of rednefs, and the furface is fomewhat rough 
to the touch. This, however, is not a fimple effloref- 
cence; for, on examining it minutely between the light 
and the eye, or with a convex glafs, the roughnefs is 
found to be occafioned by innumerable minute and pel¬ 
lucid veficles, which have been miftaken for papula:. In 
two or three days, thefe veficles, if they are not rup¬ 
tured, attain the fize of a pin’s head; and, the included 
ferum then becoming fomewhat opake and milky, the 
charader of the eruption is obvious. It foon extends 
itfelf over the body and limbs in fuccefiive large patches; 
and is accompanied by a confiderable fw'elling of the in¬ 
teguments, fuch as is feen in fmallpox and other erup¬ 
tive fevers, and by great tendernefs of the Ikin, and 
much itching. When the veficles begin to lofe their 
tranfparency, they generally burft, and difeharge, from 
numerous points, a thin acrid fluid, which feems to irri¬ 
tate the furface over which it pafles, and leaves it in a 
painful, inflamed, and excoriated, condition. The quan¬ 
tity of this ichorous difeharge is very confiderable ; and 
it gradually becomes thicker and more adhefive, ftif- 
fening the linen which abforbs it, and which thus be¬ 
comes a new fource of irritation; it emits alfo a very 
fetid odour. This procefs takes place in the fuccefiive 
patches of the eruption, until the whole furface of the 
body, from head to foot, is fometimes in a ftate of pain¬ 
ful excoriation, with deep fllfures in the bends of the 
joints, and in the folds of the Ikin of the trunk; and 
with partial fcaly incruftations, of a yellowilh hue, pro¬ 
duced by the drying of the humour, by which alfo the 
irritation is augmented. The extreme pain arifing from 
the preflure of the weight of the body upon an exten- 
five portion of fuch a raw furface, is fufficient to give 
rife to an acceleration of the pulfe, and white tongue ; 
3 
