44 
PATHOLOGY, 
to call his fydem “ the fympathetic theory,” is the mod 
important part of that theory; for the catenation, or af- 
fociation, which takes place between various functions 
when difordered, had, before his time, been very (lightly 
touched on. A partial view of one circumftance of fym- 
pathy had made Cullen attribute too much to the date 
of the jk'm in fever; and infulated faffs of the fame na¬ 
ture had impreffed almod every pathological fydem with 
error. Darwin embraced then the whole range of thefe 
afl'ociated aCtions, and formed the defign of founding a 
fydem of pathology and therapeutics on the contempla¬ 
tion of all the laws of animated nature. And hence this 
may be confidered as the firil fydem condruCted in exaCt 
conformity with phyfiology. Of this latter fubjeCt, 
Darwin, however, knew little ; and hence the failure of 
the fuperflruCture' which he raifed on it. Yet the con¬ 
ception was grand, and has been aCted upon by all patho- 
logids (ince his time. 
The three laws or principles of aCtion in the animal 
economy, which we have mentioned before, viz. i. The 
exhaudion or diminution of the fenforial powers by 
exertion; 2. The recovery or accumulation of the fame 
powers, during quiefcence, or impaired aCtion ; and 
3. The direCt and reverfe adbciation of parts, by which 
the aCtions of one part give rife to aCtions in others.; 
are the grounds of Dr. Darwin’s explanation of the phe¬ 
nomena of fevers. He fuppofes that the cold dage ac¬ 
crues in confequence of the torpor of the capillary vefiels, 
from the abflraCtion of the dimulus of heat, or other 
caufes; the hot dage, in confequence of the renovated 
activity of the capillaries, from the accumulation of 
fenforial power during that torpor. Dr. Darwin, how¬ 
ever, remarks, that this renovated activity of the capilla¬ 
ries is not owing to the renewed action of the heart, 
which forces them open by the mechanical impulfe of 
blood; that the action of the capillaries often re-com- 
mences fooner than the aCtion of the heart, thefe vefiels 
having a greater mobility than the heart and large arte¬ 
ries, as appears in the fudden blufli of (flame ; and that, 
in low fevers, the capillaries acquire increafed drength, 
as is evinced by the Audi and heat of the (kin, while the 
pulfations of the heart and arteries remain feeble. 
Hence Ample fever is of two kinds ; in one the pulfe is 
drong, in the other weak : in the fever with drong pulfe, 
not only the cutaneous capillaries, but alfo the heart and 
arteries, readily acquire a greater activity by the accu¬ 
mulation of fenforial power during the torpid date, 
which lad is farther increafed by direCt fympathy with 
the increafed activity of the capillaries ; this happens in 
drong conditutions, and is often feen in vernal intermit- 
tents : in the fever with weak pulfe, on the contrary, the 
heart and arteries do not acquire much increafe of fenfo¬ 
rial power, but continue in fome degree in their date of 
torpor, while the orgafm of the capillaries is produced ; 
whence there is a hot fit,'with feeble pulfe. 
But, when the fympathies of other parts of the fydem 
are called into aCtion, together with this torpor and or¬ 
gafm of the cutaneous vefiels, and of ,the heart and large 
arteries, the fever-fit becomes more complicated and 
dangerous. And again, when the torpor commences, 
from the operation of other exciting caufes of fever in 
other organs of the body, and extends, with the fubfe- 
quent orgafm, by direct or reverfe fympathy, to the or¬ 
gans afl'ociated with them, other various forms and mo¬ 
difications of febrile difeafe are produced. Thus, if 
the domach is affeCted with torpor, either primarily, as 
from the aCtion of contagion fwallowed with the faliva, 
or fecondarily, by its fympathy with the cutaneous capil¬ 
laries, or with fome internal vifcus; a total lofs of appe¬ 
tite occurs, followed by ficknefs and vomiting. If the 
brain is affeCted, either primarily, as by the depreflive 
padions, by exhaudion from watching, &c. or feconda¬ 
rily, as by the influence of contagious or marfli effluvia 
received into the domach or the lungs, then prodration 
of the general powers, head-ache, delirium, flupor, tre¬ 
mors, convulfions, &c. are induced. In the fame way, 
the fecretions from the internal organs, as from the kid¬ 
neys, are diminilhed when a torpor takes place in them, 
either primarily, or by fympathy with the cutaneous ca¬ 
pillaries, or other parts, and are redored with the reno¬ 
vated aCtion. Thefe phenomena take place in different 
degrees in almod all fevers, and vary according to the 
nature of the organs primarily affeCted, and to the date 
of the conditution, or of the organs individually. 
Thus, when the domach is (lightly difordered, as by in- 
digedible food, or when the vafcular fydem is deranged 
from expofure to cold, (when no inflammation is pro¬ 
duced,) the fever which enfues is mild, the brain fuffers 
little by fympathy, no delirium, See. occur, and health 
is foon redored. If, on the contrary, a virulent conta¬ 
gion aCis upon the domach, and through its medium 
upon the brain, the fenforial powers are greatly exhauded, 
and the complication of dangerous fymptoms, arifing 
from the morbid condition of the nervous fydem, and 
from the total lofs of powers in the organs of digedion, 
occurs, condituting the contagious, nervous, and malig¬ 
nant, fever, or typhus, under its various forms and deno¬ 
minations. 
Dr. Darwin explains the peripneumony as “generally 
induced by the patient refpiring very cold air, and this 
efpecially after being long confined to warm air, or after 
being much fatigued or heated by exceflive labour or ex- 
ercife. For we can cover the (kin with more clothes, 
when we feel cold; but, the lungs not having the per¬ 
ception of cold, we do not think of covering them, nor 
have we the power of covering them, if we defined it; 
and the torpor thus produced is greater, or of longer du¬ 
ration, in proportion to the previous expenditure of fen¬ 
forial power by heat or exercife. This torpor of the 
lungs affeCts the (kin with (huddering, and the domach 
is alfo fecondarily affeCted ; next follows the violent ac¬ 
tion of the lungs from the accumulation of the power of 
irritation, and an inflammation of them follows this vio¬ 
lent aCtion, &c.” 
This author clafled difeafes according to their fuppofed 
origin in didurbed dates of the vital powers; but the 
arrangement is quite fanciful, to fay the lead of it; and 
the frequent repetitions of fpecies which occur under dif¬ 
ferent heads, (how its imperfection. Thus, he divided 
difeafes into four kinds; thofe of irritation, fenfation, 
volition, and affociation ; and, forming his therapeutical 
doCtrines according to the fame views, he arranged the 
materia medica intofeven claffes. 1. Nutrientiu, or thofe 
things which preferve in their natural date the due ex¬ 
ertions of all the irritative motions. 2. Incitantia , or 
thofe things which increafe the exertions of all the irri¬ 
tative motions. 3. Secernentia, or thofe things which in¬ 
creafe the irritative motions which conflitute fecretion. 
4.. Sorbentia, or thofe things which increafe the irritative 
motions which conditute abforption. 5. Invertentia , 
or thofe things which invert the natural order of the 
fucceffive irritative motions. 6. lievertenliu, or thofe 
things which reflore the natural order of the inverted ir¬ 
ritative motions. 7. Turpentiu, thofe things which di- 
minifli the exertions of all the irritative motions. 
This theory was never very generally received in Eng¬ 
land ; but, dripped of the hypothetical phrafeology and 
much modified, it appears to have been taken up and il- 
ludrated with much fuccefs by the celebrated Hufeland 
in Germany. 
We are now arrived at a period when phyficians, no 
longer dazzled by brilliant hypotiiefes, required in pa¬ 
thology and phyfiology the clofe analogical reafoning 
which had been found fo ufeful in every other depart¬ 
ment of fcience. Hence fyflems of medicine, incapable 
of embracing all known forms of difeafe, have ceafed to 
exid. Imprefi'ed with the conviction that our dock of 
known faCts required much addition ere it could be ge¬ 
neralized, the pathologids of our time have individually 
attached themfelves to the acquilition of further expe- 
s ~ rience 
