December 4 marks the passing of Luigi Galvani. Galvani was an Italian physician who first identified electrical activity in living tissue. Towards the end of the 18th Century, one of the newest and cutting-edge scientific fields of study was electricity. Galvani acquired his own electrostatic machine to generate static electricity and Leyden jars to store static electricity. With these, he began experimenting with living tissue. He found he could cause muscle contractions in frog legs through electrical shocks to the nerves. He also found he could get the same contraction without electricity if he used electrodes of different metals. He concluded living tissue had some ‘vital force’ or what he called animal electricity. This natural electricity was a fluid excreted by the brain that flowed through the body via the nervous system.
Later, Alessandro Volta showed there were no animal electricity fluids, and the electricity came from the different metal electrodes in a moist environment. Galvani did manage to demonstrate electrical forces do exist within living tissue and founded electrophysiology, the study of electricity in living systems.
Notable Science History Events for December 4
1978 – Samuel Abraham Goudsmit died.
Goudsmit was a Danish-American physicist who with George Eugene Uhlenbeck formulated the concept of electron spin. Electron spin is one of the four main quantum numbers for an electron’s state in an atom and explains many aspects of atomic magnetic dipole moments that cannot be explained by classical physics.
1945 – Thomas Hunt Morgan died.
Morgan was an American geneticist who was awarded the 1933 Nobel Prize in Medicine for discovering the role chromosomes play in heredity. He made an extensive study of the fruit fly, Drosophila. Morgan’s group identified several sex-related traits that could be related to the chromosomes of the flies. When the traits were compared to the chromosomes of the flies, each trait was represented with a minor chromosome change.
Read more about Thomas Morgan on September 25 in Science History.
1935 – Charles Robert Richet died.
Richet was a French physiologist who was awarded the 1913 Nobel Prize in Medicine for his research into anaphylaxis. Anaphylaxis is an acute allergic reaction where extremely small doses of an allergen may cause life-threatening anaphylactic shock.
Richet was also a leading researcher into parapsychology. He was interested in extrasensory perception (ESP) and hypnotism and believed there was a physical cause for supposed supernatural events. He is also credited with coining the word ‘ectoplasm’ to describe this physical cause.
1908 – Alfred Day Hershey was born.
Hershey was an American biologist who shares the 1969 Nobel Prize in Medicine with Salvador E. Luria and Max Delbrück for their work with bacteriophages. They found when two different viruses infect the same bacteria, the two may exchange genetic information.
1893 – John Tyndall died.
Tyndall was an Irish physicist known for his discoveries in the properties of air, magnetism, and infrared radiation. He showed several gasses in air absorbed radiant heat or infrared radiation. Water vapor, carbonic acid (carbon dioxide), ozone, and methane absorbed heat on their own better than the atmosphere itself. He showed oxygen, hydrogen, and nitrogen gasses absorbed nearly no radiant heat. He also showed the formation of dew and frost was caused by a loss of heat energy in the air.
Tyndall is also known for describing the scattering of light through colloids. He showed the intensity of scattered light is proportional to the fourth power of the frequency of the incident light. You can see this effect by the blue coloring of smoke, motor vehicle exhaust, or even stirring flour into water. This effect is known today as the Tyndall effect or Tyndall scattering.
Tyndall became an avid mountaineer while studying glaciers and glacial movement. He was one of the first climbers to reach the tops of several Swiss alp peaks like the Weisshorn and the Matterhorn.
Tyndall was also a popular writer and public speaker. He was known for his descriptive lectures and ability to explain complex ideas to unscientific audiences. He published several books explaining science and physics to wide audiences. He also lectured on the separation of religion and science.
Tyndall suffered from chronic insomnia and would take chloral hydrate to help fall asleep. His wife accidentally poisoned him when she prepared too much of the drug.
1798 – Luigi Galvani died.
1680 – Thomas Bartholin died.
Bartholin was a Danish anatomist and physician who was the first to describe the entire human lymphatic system. He identified the thoracic duct as the entry point for lymphatic fluids to enter the bloodstream. The lymphatic system is an important part of how the body constructs an immune response to infections.