ANATOMY. 
that quantity prior to every pulse. From 
whence is it received, unless the blood cir- 
culates? Harvey tied an artery, and the 
corresponding vein received no blood ; he 
tied a vein, and all its branches, and those 
of the corresponding artery, were choaked 
with blood, even to the entire obstruction 
of circulation and motion. But Harvey 
was not acquainted with the direct commu- 
nication that exists between these vessels. 
He imagined that the blood transuded from 
the arteries into the veins through a spongy 
substance. Much yet remained to be as- 
certained by microscopical observations, and 
subtile anatomical injections and dissections. 
As opportunities of dissection became 
more numerous, the defects of the old 
writers in anatomy were discovered. In- 
genious men, having gone through their edu- 
cation, determined to consult nature for 
themselves. It is not to be wondered at 
that errors and deficiencies in anatomy 
were found in every page of the works of 
Galen, to say nothing of Hippocrates, since 
the human body, in his time, could not be 
consulted for information. The authority 
of the Greek writers on these subjects was 
quickly demolished, and anatomy began to 
be taught from the subject itself. We must 
not omit the influence, which the writings of 
our immortal coxintryman Bacon had on the 
prosecution of natural knowledge, and in 
every species of reasoning. The philosophy 
of Aristotle was driven from the pre-eminent 
station, which it had so long occupied, to 
make room for the only solid and secure 
method, of observation, experiment and in- 
duction. At tin's time the Academy del 
Cimento arose in Italy, the Royal Society 
in London, and the Royal Academy in 
Paris. From this period, the important 
doctrine of rejecting all hypothesis, or ge- 
neral knowledge, till a sufficient number of 
facts shall have been ascertained, by care- 
ful observation and judicious experiments, 
has been every day growing into more cre- 
dit. The anatomists and physiologists of 
these times distinguished themselves by a 
patient observation of nature itself, and an 
accurate account of the phenomena which 
they observed. 
After the discovery and knowledge of 
the circulation of the blood, the next ques- 
tion would naturally be about the passage 
and route of the nutritious part of the food, 
,or chyle, from the bowels to the blood-ves- 
sels. The name of Aselli, an Italian physi- 
cian, is rendered illustrious by the discovery 
of the vessels which carry the chyle from 
the intestines. He observed them full of a 
white liquor on the mesentery of living ani- 
mals, and from this circumstance called 
them milky or lacteal vessels. For many 
years the anatomists in all parts of Europe 
were daily opening living animals, either to 
see the lacteals, or to observe the pheno- 
mena of the circulation. In making an ex- 
periment of this kind, Pecquet in France 
was fortunate enough to discover the tho- 
racic duct, or common trunk of all the lac- 
teals, which conveys the chyle into the sub- 
clavian vein. And now the lacteals having 
been traced from the intestines to the tho- 
racic duct, and that duct havingbeen traced 
to its termination in a blood-vessel, the 
passage of the chyle was completely made 
out. The discovery of £he absorbent ves- 
sels in other parts of the body, where they 
are known by the name of lymphatics, from 
the transparent colour of their contents, 
very soon followed that of the lacteals and ; 
thoracic duct. Rudbek, a Swede, is gene- 
rally allowed to have been the first who dis- 
covered these vessels ; but this honour was 
disputed with him by Bartholin, a learned 
Dane. By these vessels the old particles! 
of our bodies, which are no longer fit to re- 
main in it, are removed and conveyed into 
the blood, to be eliminated by the excre- 
tory organs. 
Leeuenhoeck took up the subject of ana- 
tomical inquiry, where others had left it. 
He investigated the minute structure of the 
body by the help of magnifying glasses; 
and was thereby enabled to demonstrate 
the circulation of the blood in the pellucid 
parts of living animals ; the red globules 
of the blood, and the animalcula of the 
semen were first observed by this anatomist. 
Malpighi also directed his attention chiefly 
to the development of minute structure, as 
that of the glands or secretory organs of the 
body. 
About this time anatomy made two great 
steps, by the invention of injections, and the 
method of making anatomical preparations. 
For these we are indebted to the Dutch, 
particularly Swammerdam and Ruysch. The 
anatomists of former ages had no other 
knowledge of the blood-vessels, than what 
they could collect from laborious dissections, 
and from examining the smaller branches of 
them upon some lucky occasion, when they 
were found more than commonly loaded 
with red blood. But filling the vascular 
system with a bright coloured wax enables 
us to trace the large vessels with great ease, 
renders the smaller much more conspicuous^ 
r 
