Archimedes, Palimpsest (287-212 bc), preeminent Greek mathematician and inventor, who wrote important works on plane and solid geometry, arithmetic, and mechanics.

In mechanics, Archimedes defined the principle of the lever and is credited with inventing the compound pulley. During his stay in Egypt he invented the hydraulic screw for raising water from a lower to a higher level. He is best known for discovering the law of hydrostatics, often called Archimedes' principle, which states that a body immersed in fluid loses weight equal to the weight of the amount of fluid it displaces. This discovery is said to have been made as Archimedes stepped into his bath and perceived the displaced water overflowing.

Archimedes helped the king to determine how much gold was in the crown and used his volume displacement method like in his bathtub experiments. He uses this principle to apply to Descartes idea.

He had a person place their arm in a tube of water and then contract and extend. If there were animal spirits that moved from the brain into the arm for movement, then the arm should increase in size and displace more water; however, the water did not go up. This disproved Descartes theory.


Swammerdam, Jan (1637 Ė 1680) a 17th century Dutch microscopist, made major discoveries in medicine and anatomy. Above all, he made a decisive contribution to the development of biology and a materialist understanding of nature.

Swammerdam surgically isolated a muscle and disconnected the nerve from the brain and showed that stimulation of nerve equaled movement.



Magendie, who was born in France, obtained all of his education including his medical training in his native country.  Hs is identified as a physician and a physiologist. Early, he was interested in the physiology of digestion, later his areas of study included the heart, the blood- Magendie repeat Charles Bellís work on the division of anterior and posterior spinal roots and demonstrated that the posterior spinal roots and demonstrated that the posterior root stimulation elicited pain while this stimulation of the anterior root produced motor effects.  He described the apertura medialis ventriculi quarte- the foramen of Magendie. He showed that by cutting the posterior spinal nerve lead to loss of feeling, but kept motor activity. Cutting the anterior branch did the opposite Ė still feeling, loss of motor.

 Reflex Arch:


A reflex is an unlearned correlation between a class of stimuli and a class of responses. A reflex is not a stimulus or a response. Itís the relationship between the two. A lot of behavior is controlled reflexively.



Sechenov, born in Russia, was known as the Father of Russian physiology. He introduced electrophysiology into laboratories and also into teaching. His life work was always concentrated on neurophysiology. He wrote a major classic "The Reflexes of the Brain." He also maintained that physiochemical factors in the environment of the cell are of equal if not greater importance. He was in conflict constantly with the government and his colleagues. He will also be remembered for his intellect and his knowledge, as well as for his scientific achievements.

Sechenov said that all behavior can be accounted for by reflexes (unconditioned responding). He proposed a reflexology. It is a replacement for psychology. He said some stimuli are subtle and make some behaviors hard to predict. The only problem with this was that there was no learning involved.


Pavlov, Ivan Petrovich (1849-1936)

Russian physiologist Ivan Pavlov won the 1904 Nobel Prize in physiology or medicine. Although best known for his work on reflex behavior, Palov made major scientific contributions to understanding the physiology of the digestive stystem.



Russian psychologist Ivan Petrovich Pavlovís name has become synonymous with the research he conducted on reflex behavior in animals. Pavlov demonstrated in experiments that dogs that heard a bell ring at feedings became conditioned to salivate at the sound of the bell. Pavlov, who also studied the nervous system, heart, and digestive system, is shown here, third from left, at work in his lab.