Andreas Vesalius (1514-1564)

Andreas Vesalius was an anatomist, physician, and also an author of one of the most influential books on human anatomy. He is considering as the “founder of modern human anatomy”. His important innovations were to perform postmortem dissections and to make use of illustrations in the teaching of anatomy. He is also known as Andreas Vesal and Andre Vesale.

Andreas Vesalius was born on December 31, 1514 in Brussels, then in the Holy Roman Empire to a family of physicians. He was the son of Andries van Wesele. His father enrolled him in the Brethren of the Common Life School in Brussels to learn Greek and Latin according to standards of the era. In 1528, He entered the University of Louvain taking arts, but in 1532, he decided to pursue a career in medicine at the University of Paris, where he moved in 1533. Here he studied the theories of Galen under the auspices of Jacques Dubois and Jean Ferne. It was during this time that he developed his interest in anatomy.

On graduation he was immediately offered the chair of Surgery and Anatomy at Padua. He also guest lectured at Bologna and Pisa. Previously these topics had been taught primarily from reading classic texts, mainly Galen, followed by an animal dissection by a barber-surgeon whose work was directed by the lecturer. In 1538 he published a letter on bloodletting. This popular treatment for almost any illness, but there was some debate about where to take the blood from. In 1541, Vesalius uncovered the fact that all that Galen’s research had been based upon animal anatomy rather than the human; since dissection had been banned in ancient Rome, Galen had dissected Barbary Apes instead, and argued that they would be anatomically similar to humans.

Vesalius, undeterred, went on to stir up more controversy, this time proving wrong not just Galen but also Mondino de liuzzi and even Aristotle; all three had made assumptions about the functions and structure of the heart had four chambers, the liver two lobes, and that the blood vessels originated in the heart, not the liver. After struggling for many days with the adverse winds in the Ionian Sea, He was wrecked on the island of Zakynthos. Here he soon died in such debt that, if a Benjamine factor had not paid for a funeral, his remains would have been thrown to the animals at the time of his death on October 15, 1564 he was scarcely fifty years of age.

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Amedeo Avogadro (1776 – 1856)

Amedeo Carlo Avogadro was an Italian savant. He is renowned for his contribution to molecular theory, including what is known as Avogadro’s law. He was born in Turin, Itlay on 9 August, 1776. He was the son of Count Filippo Avogadro and Anna Maria Vercellone. His father was a distinguished lawyer and civil servant.

Avogadro went to school in Turin. Coming from a family of well established lawyers, Avogadro was guided toward a legal career, and became a bachelor of jurisprudence in 1792, at the young age of just 16 years. Four years later he gained his doctorate in ecclesiastical law and began to practice. In 1801 he was appointed secretary to the prefecture of the department of Eridano. In 1820, he became professor of physics at the University of Turin. He married Felicita Mazzé and they had six children.

As we all know today, Avogadro’s number is very large, the presently accepted value being 6.0221367 X 1023 . The size of such a number is extremely difficult to understand. Cannizarro, around 1860, used Avogadro’s ideas to obtain a set of atomic weights, based upon oxygen having an atomic weight of 16. In 1865, Loschmidt used a combination of liquid density, gaseous viscosity, and the kinetic theory of gases, to establish roughly the size of molecules, and hence the number of molecules in 1 cm3 of gas.

Avogadro died on the 9th July, 1856. He was described as religious, but not a bigot.