PATHOLOGY, 
arifing from temper, age, conftitution, or other adven¬ 
titious circumftances. 
A fyftem of therapeutics founded on fuch a bafis could 
fcarcely deviate from the right path; and accordingly 
the works of this author remain molt important ftudies, 
whether regarded as indications to the art of diagnofis, 
or to the cure of difeafe. His pradtice was in the molt 
eminent degree fuccefsful; and among the remedies he 
had recourfe to we may remark many which are again 
firmly eltablifhed after having long fallen into difcredit 
under the inaufpicious influence of fpeculative theorifts. 
Among thefe, the ufe of bleeding, and other antiphlo- 
giftic methods, in the treatment of continued eruptive 
fevers, has conduced very materially to the prefervation 
of the lives of our fpecies. We may remark, that in this 
aflumption we are borne out by the fatality which oc¬ 
curred during the exhibition of alexipharmics and hot 
cordials by the chemifts, which the cooling fyftem has 
very much obviated. The dodlrines of Sydenham, not- 
withftanding the interefting ftyle in which they were 
written, the fame they acquired for their author, and 
their confonance with nature, were by no means gene¬ 
rally received ; and the chemical dodtrines continued to 
be advocated by many till the commencement of the fol¬ 
lowing century. 
In proportion as true chemical fcience advanced, the 
partiality for chemical explications of the functions of 
the living fyftem abated ; and phyficians feem to have 
difcovered, for the firft time, that the theory of the hu¬ 
mours, even with all the improvements which it derived 
from the corpufcular philolophy, threw no light whatever 
on the adtions of the folids. A new hypothefis, there¬ 
fore, was projedted; and, as men in avoiding one error 
are apt to run into the oppoiite extreme, phyfiologifts 
now attempted to explain all the phenomena of life ac¬ 
cording to the mere mechanical powers of the organs, and 
to reduce the laws of the animal economy to the rigid 
calculations of geometry. They imagined, that they 
could illuftrate every operation of the human body, by 
comparing it to a fyftem of ropes, levers, and pulleys, 
limited with a number of rigid tubes of different lengths 
and diameters, containing fluids, which, from variations 
in the impelling caufes, moved with different degrees of 
velocity. When the fibres of this machine were not 
fufficiently flexible ; when the pulleys and joints of the 
levers were not kept in fufficient repair; or when the 
apertures of the pipes were not fufficiently free ; the 
movements were neceffarily fufpended, or lefs perfedlly 
performed ; and they were only to be brought into pro¬ 
per regulation, according to the pradtitioners who adopted 
this fanciful theory, by removing the above-defcribed 
impediments. The cotnpofition of the fluids was fup- 
poled to be the refult of their motion in the tubes ; and 
in thefe nothing was attended to but the forces of gra¬ 
vity and cohefion ; as in calculating the adtion of a 
pump, or other hydraulic engine. “ If the chemical 
fchool,” to ufe the words of Sprengel, “ had degraded 
the phyfician to the rank of a brewer or diftiller, the 
difciples of the iatro-mechanical fchool, on the other 
hand, were glad to be efteemed as hydraulic engineers; 
and feveral of them, in fadt, ferved in the double capa¬ 
city of engineers and profeffors of medicine.” One of 
them, Dionis, a profeuor of furgery at the Jardin du 
Roi, went fo far as to compare the circulatory fyftem to 
the water-works at Marly, by which the water of the 
Seine is raifed to confiderable height, and from thence 
made to fall again upon the great wheel. 
Among the caufes which conduced to the eftablifliment 
of this fedt, the difcovery of the circulation of the blood 
is the moft prominent. When it was found that the 
blood flowed in a regular manner, through certain con¬ 
duits, from the heart, and returned to that organ, by 
other veffels, from the extremities, phyficians fet about 
calculating the mechanical force which they luppofed ne- 
ceffary for enabling the heart and arteries to produce this 
effedl; and, elated with their apparent fuccefs, were led 
by degrees to transfer their calculations to the other 
fundtions of the body. Geometry had become the pre¬ 
vailing ftudy of the learned ; and focieties for the pro¬ 
motion of experimental philofophy were eftablifhed in 
the different countries of Europe, among which the 
Florentine Academy del Cimento took, in fome meafure, 
the lead. It was in Italy that mathematics had been 
moft afliduoufly cultivated ; and it was there that the 
firft attempt was made to introduce them into medicine. 
In the year 1614, Sandtorius publifhed his Medicina Sta¬ 
tical in which heendeavoured to (how the great influence 
which the infenfible perfpiration has upon health, and 
to calculate with precifion all the variations in its quan¬ 
tity, in the different conditions of the body. According 
to Iris theory, difeafes originated from the noxious par¬ 
ticles of the food being retained in the fyftem, in con- 
fequence of the ftoppage of the tranfpiration; and, till 
the latter fundtion was reftored to the proper ftandard, 
no cure could well take place. Sandtorius diftinguiffied 
the different alimentary matters according to their fpe- 
cific gravities, and according as they appeared more or 
lefs fitted to pafs off in the way of infenfible perfpiration. 
He even ventured to apply his maxims to the paflions of 
the mind ; fhowing how joy and equanimity favoured the . 
excretions, while forrow and fear impeded them ; how 
fevers and melancholy arofe from the obftrudted perfpi- 
rable matter, where grief was long continued ; and how 
they were to be removed by reftoring the fufpended ex¬ 
halation. Among the aphorifms of Sandtorius, there are 
many found obfervations ; and medical fcience is under 
confiderable obligations to him for having diredted the 
attention of phyfiologifts to the fundtions of the fkin, 
which, till then, had been in a great meafure overlooked ; 
but his views, like thofe of moft theorilts, were far too 
partial; and there can be little doubt that, in one re- 
fpect, they had a moft injurious influence, viz. by en¬ 
couraging phyficians in the univerfal employment of fu- 
dorifics, to which they were already too prone; and no 
one will now fubfcribe to the judgment of Boerhaave, who 
fays of Sandtorius and his work, “ Nullus medicorum, 
qui ante eum fcripferunt; cardinem rei ita adtigit; nec 
ullus liber in re medica ad earn perfedtionem fcriptus 
eft.” 
The mechanical philofophers began by calculating the 
force of the contradtile power of the heart neceffaVy to 
produce the phenomenon of circulation : but in this cal¬ 
culation they proceeded on the erroneous datum, that 
the refiftance oppofed by cohefion and gravity was the 
fame in living veflels as in inanimate pipes. Even if this 
fuppofition had been true, yet they had no means of 
meafuring the numerous diameters of thefe veflels, their 
curves, angles, &c. circumftances indifpenfably necef- 
fary to be known before the above-mentioned calculation 
could have been made. A more ingenious mode of il- 
luftrating the procefs of circulation was that adopted by 
Borelli. This author affumed that the power of a mufcle 
was in diredl ratio to the fize of fibrous portion: -hence, 
taking the deltoid mufcle for an example, and having 
found the force that mufcle was capable of exerting, he 
next proceeded to calculate the force which the contrac¬ 
tion of the heart mult exert according to its proportion- 
ably larger fize. This aflumption, however, is unfounded; 
for exercife increafes the power of a mufcle, without, 
in every inftance, increafing its fize: nor does it appear 
by what means he could precifely infulate tire adtion of 
the deltoid mufcle, feeing that it is infeparably con¬ 
joined with feveral others which co-operate with its mo¬ 
tions. The experiments of Kiel and others, though 
founded on different aflumptions, were not more fatis- 
fadtory than thofe of Borelli. At this period, however, 
geometry was fuch a favourite purfuit among the learned, 
that its cultivation rendered the mind almoft diffatisfied 
with every theory which did not bear the teft of mathe¬ 
matical demonftration. Thefe calculations therefore, 
to 
