William Harvey , English doctor (1578 with Folkestone (Kent) - (1657 with London)

Biography

Wire of a easy Yeoman of the Kent, Harvey accepted its first instruction in King' S School of Canterbury, then studied with the Gonville and Caius College (Cambridge), of which it was accepted laid off are arts in 1597. He attended then the Université of Padoue, where he had as a professor Hieronymus Fabricius and the philosopher aristotelician Cesare Cremonini, and was graduate doctor of medicine in 1602. Of return in England, he married the girl of a famous London doctor named Lancelot Browne, of which he did not have a child. He officiated with the St Bartholomew' S Hospital of London (1609-43) and was elected member of the Royal College off Physicians .

Having served the party of the king during the civil war, he saw himself stripped his places, and lived then in the retirement.

When it ceased practicing medicine to St Bartholomew' S Hospital, it is established in Oxford and where it had been named Directeur ( Warden ) of the Merton College (Oxford). In 1651 William Harvey made a gift with the college to build and fund a library, which was inaugurated in 1654. In 1656 it created funds to remunerate a librarian and to say a prayer each year, ceremony which remained until today in its honor. Harvey also bequeathed funds for the creation of a school of boy gifts his birthplace (Folkestone): the Harvey Grammar School , which opened its doors in 1674, always exists.

Blood circulation according to Harvey

It was delivered with heat to the experimental Anatomie, visited to inform the scientists of the France, the Italy (Realdo Colombo and Fabrice d' Acquapendente), and of the Germany, set at London in 1604, was named in 1613 professor of anatomy and of surgery to the College of medicine of this city, became doctor of Jacques Ier of England and Charles Ier of England, and chief of the Collège of Merton to Oxford.

One owes him, inter alia discoveries, that of the laws of the circulation the blood which it communicated as of 1619 with its pupils, and with the public in 1628.

Evolving/moving beyond the typical framework of the Rebirth based on the idea of Aristote of a bond between Macrocosm and Microcosm (“ the heart is with the body what the sun is with cosmos ”), Harvey notes by its observations with Padoue that:

• as had shown it Ibn year-Nafis, the idea that a mixture between two kinds of different bloods is not possible (blood purified by the lung, cold and rough blood, heat)
• the assumption of Jean Fernel on the bond between the systole and the ejection of blood is exact.

It is known that there exists a closed circuit for small circulation, but it speculates that he is the same for the great circulation which would be also a closed circuit.

To prove its assumption, Harvey resorts to a quantitative reasoning:

• it studies hearts of all kinds, and it measures, on average, which quantity of liquid can be contained in the cavities of a heart: a heart contains two ounce S.
• it also measures the frequency of the cardiac beats per unit of time: 72 beats per minute
• it thus calculates that the heart brews 8.640 ounces per hour, that is to say 259 kg of blood brought to the periphery.

He says himself then: “and if there were a return of blood in the middle? ”

It proves this theory by the experiment of the garrot: one can thus observe the flow of blood in the veins as the garrot is loosened. The structure in which this return is done, they are the surface veins: in which one makes the blood tests today. It is about a progressive return.

This experiment is very reproducible, and realizable on an human being under any condition of the daily life. The idea of the repetition constitutes a proof here; indeed, Harvey thus proves its theory with its contemporaries.

What misses with this theory to be complete and explain the blood circulation as a whole, it is the capillary concept of .

We are at this time there with the whole beginning of the Microscopie. There is thus an incapacity to determine continuity between large arterial vessels and large venous vessels because the system of the capillary network is invisible, it is him which is responsible for the exchanges with fabrics.

Which is the interest for the blood which turns in round to pass by the lungs? And from which heat comes?

This theoretical upheaval obliges with a rebuilding of a whole physiological system.

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