ANATOMY. 



This he did, and thereby rendered his 

 name immortal. 



It seems proper in this place to review 

 the several steps which were made in the 

 investigation of this important subject. 

 Hippocrates believed that all the vessels 

 communicated with each other, and that 

 the blood underwent a kind of flux and re- 

 flux from and to the heart, like the ebbing 

 and flowing of the sea. The anatomists at 

 Alexandria adopted a wrong but ingenious 

 opinion ; as they found the arteries empty, 

 and the veins containing blood, in their 

 dissections, they imagined that the former 

 were tubes for the distribution of air, and 

 gave them that name, which they have re- 

 tained ever since ; and that the veins were 

 the only channels for the blood. Galen 

 ascertained that the blood flowed both by 

 the arteries and veins, though he knew not 

 then its natural course. On the revival of 

 anatomy in Europe, the pulmonary circu- 

 lation was known to many eminent men. 

 This was certainly the case with Servetus, 

 who fell a sacrifice, on account of his reli- 

 gious opinions, to the savage bigotry and 

 intolerance of Calvin. Fabricius ab Aqua- 

 pendente, the preceptor of our famous 

 Harvey, particularly described the valves 

 of the veins, the mechanism of which 

 would absolutely prevent the blood from 

 flowing in those vessels towards the ex- 

 tremities. When Harvey returned from 

 his studies in Italy, his attention being ex- 

 cited to the subject, he began those expe- 

 riments, by which he learned and demon- 

 strated the fact of the circulation. Har- 

 vey's first proposition of the subject im- 

 presses conviction so strongly on the mind, 

 that we are left in perfect astonishment, 

 how a circumstance so luminously evident 

 should have remained so long unobserved. 

 It must be granted, that the heart projects 

 about two ounces of blood into the arte- 

 ries at every pulse ; what then, it may be 

 asked, becomes of this large quantity of 

 blood, unless it circulates ? It must be 

 granted that the heart receives that quan- 

 tity prior to every pulse. From whence is 

 it received, unless the blood circulates ? 

 Harvey tied an artery, and the correspond- 

 ing vein received no blood ; he tied a vein, 

 and all its branches, and those of the cor- 

 responding artery were choaked with 

 blood, even to the entire obstruction of 

 circulation and motion. But Harvey was 

 not acquainted with the direct communi- 

 cation 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 ascertained by microscopical observa- 



tions, and subtle anatomical injections 

 and dissections. 



As opportunities of dissection became 

 more numerous, the defects of the old wri- 

 ters in anatomy were discovered. Ingeni- 

 ous 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 countryman, Ba- 

 con, had on the prosecution of natural 

 knowledge, and in every species of rea- 

 soning. 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 obser- 

 vation, experiment, and induction. At this 

 time the Academy del Cimento arose in 

 Italy, the Royal Society in London, and the 

 Royal Academy in Paris. From this peri- 

 od, the important doctrine of rejecting all 

 hypothesis, or general knowledge, till a 

 sufficient number of facts shall have been, 

 ascertained, by careful observation and ju- 

 dicious experiments, has been every day 

 growing into more credit. The anatomists 

 and phisiologists of these times distin- 

 guished themselves by a patient observa- 

 tion of nature itself, and an accurate ac- 

 count of the phenomena which they ob- 

 served. 



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- 

 vessels. The name of Aselli, an Italian 

 physician, 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 mysen- 

 tery of living animals, and from this cir- 

 cumstance 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 phenomena of the circula- 

 tion. In makingan experiment of this kind, 

 Pecquet,in France, was fortunate enough 

 to discover the thoracic duct, or common 

 trunk of all the lacteals, which conveys the 

 chyle into the subclavian vein. And now, 

 the lacteals having been traced from the 

 intestines to the thoracic duct, and that. 



