Sunday, September 30, 2012
Perrin's early work on cathode rays proved that they were made of negatively charged particles. His work covered a number of topics in physics including the effects of x-rays on the conductivity of gasses, fluorescence, and the radioactive disintegration of radium. He suggested that stars obtained their energy from the thermonuclear reactions of hydrogen. He wrote numerous books and papers including Les Atomes where he describes his studies on Brownian motion, which confirmed the atomic theory, that all matter is made of atoms.
In 1905 Albert Einstein had published a paper on Brownian motion describing how it was the result of atomic theory. Brownian motion is the random motion of particles suspended in a liquid, discovered in 1827 by Robert Brown, an English botanist who watched pollen particles suspended in water. Suspended in a liquid, the particles are constantly bombarded by moving molecules of the liquid. This causes the visible particles to move in random directions. Einstein's paper was theory and it was Perrin who experimentally demonstrated that matter is made of molecules. Perrin was able to use Brownian motion to determine a value for Avagadro's constant that closely agreed with the value obtained using Dalton's law of molecular motion. Avagadro's constant is the number of molecules in a mole of a substance. For his work, proving the atomic theory Perrin was awarded the 1926 Nobel Prize for Physics.
Perrin was the recipient of numerous other awards, including the Joule Prize from the Royal Society in 1896 and the La Caze Prize from the Paris Academy of Sciences in 1914. He was made a commander in the French Legion of Honor in 1926 and a commander in the Legion of Leopold (Belgium). He was awarded numerous honorary doctorates.
In 1940 he fled German occupied France to the United States where he died on April 17, 1942. After World War II, in 1948, his remains were returned to France aboard the light cruiser Jeanne d'Arc and he was buried in the Pantheon in Paris, France.
Allison, Andy; "Jean Perrin and Atomic Theory: Calculating Avagadro's Constant"; Physics @ Suite 101; October 3, 2008
Jean Perrin Nobel Biography
Jean Perrin Wikipedia Entry
Sunday, September 23, 2012
Yersin quickly tired of working for Pasteur, who was notorious for taking credit for the work of those beneath him, so he signed on as a ship's doctor with Messangeries Maritimes, a shipping company. His duties were light and his first voyage took him to Saigon, Vietnam. Yersin spent many years in Vietnam, some on expeditions into unexplored parts and is a honored hero for the free medical consultations he gave. Streets bearing his name remained named after him following the communist revolution.
In 1894 he was sent by the Pasteur Institute and the French government to Hong Kong to investigate an outbreak of plague. When he arrived he found that Shibasaburo Kitasato, who had recently discovered the role of Clostridium tetani in lockjaw, was already working on isolating the bacterial cause of the plague. Yersin saw that Kitasato was culturing bacteria from the blood and organs of patients, but not the characteristic bubos of bubonic plague. Yersin was able to bribe two British sailors and gain access to the morgue. Using a sterile pipette he punctured the infected lymph node of a recently dead patient. He found faintly gram negative staining bacilli (rod-shaped bacteria) in the material he withdrew from the lymph node. He injected mice with the lymph node material and they quickly died. Autopsies showed the same slightly gram negatively staining bacilli.
Kitasato was quick to publish his results and claim credit for the discovery of the bacteria responsible for plague. Kitasato's cultures turned out not to be pure for the causative organism and Yersin was allowed to name the new bacteria. Pasturella pestis was his choice, honoring Pasteur, but since 1944 it has been Yersinia pestis. Yersina and Kitasato are considered co-discoverers of the organism.
In addition to his medical work, Yersin also tried his hand at agriculture, importing the Brazilian rubber tree and the quinine tree from the Andes to Vietnam. He was the director of the medical school at Ha Noi, Vietnam in its first two years (1902-1904).
He died on March 1, 1943.
Burns, William; "Alexandre Yersin and His Adventures in Vietnam"; Mill Hill Essays 2003; National Institute for Medical Research; 2003
Maki, Rebecca; "The Discovery of Yersinia pestis"; at antimicrobe.org
Alexandre Yersin Wikipedia Entry
Monday, September 17, 2012
Hoppe-Seyler in addition to being a biochemist was an inorganic chemist and was interested in what chemical elements made up living tissues. In his lab Kossel studied "nucleins" the newly isolated contents of cell's nuclei. Nucleins had been discovered by Friedrich Miescher in 1869. He had determined that they were chemically different from protein, being more acidic. In 1883 Kossel became the director of the Chemistry Division of the Physiological Institute at the University of Berlin. In the period from 1885 and 1901 Kossel isolated from nuclein the five nucleic acid bases that make up DNA and RNA: adenine, guanine, cytosine, thymine and Uracil. These five bases are the letters of the genetic code that code for proteins. In DNA, the instructions for construction proteins are written in four nucleotides: adenine, guanine, cytosine and thymine. In messenger RNAs, the translations of the DNA code that are sent to ribosomes, where proteins are made, thymine is replaced with uracil.
In 1895 Kossel became a professor of physiology and director of the Physiological Institute at the University of Marburg. In Marburg Kossel began to investigate the structure of proteins. In 1896 Kossel isolated histidine, an amino acid with a imidazol functional group. Kossel also was the first to isolate theophyllin a therapeutic drug found in cocoa and tea. In 1901 Kossel became the director of the Physiological Institute at Heidelberg University. In 1910 Kossel was awarded the Nobel Prize "in recognition of the contributions to our knowledge of cell chemistry made through his work on proteins, including the nucleic substances". In 1924 Kossel became professor emeritus at Heidelberg, but continued teaching. His research also continued as he continued working on determining the structure of proteins.
Kossel died on July 5, 1927.
Jones, Mary Ellen; "A Biographical Sketch of Albrecht Kossel"; Yale Journal of Biology and Medicine(1953)26:80-97
Albrecht Kossel Nobel Biography
Albracht Kossel Wikipedia Entry
Sunday, September 9, 2012
Coues' military career took him all over the United States, with postings in Arizona, North Carolina, California and North Dakota. Coues was an prolific writer and wrote many works on ornithology and natural history. In the Army he got the chance to join expeditions that explored parts of America, serving as both naturalist and surgeon on the United States Northern Boundary Commission form 1873-1876 and from 1876 to 1880 he served as secretary and naturalist to the United States Geological and Geographical Survey of the Territories. While in the army he authored 300 works and papers. He resigned from the army in 1881 to devote himself more fully to literary and scientific pursuits. After resigning from the Army he returned to Washington D.C. In 1877 he was appointed professor of Anatomy at the National Medical College and that same year he was elected to the National Academy of Sciences. He was one of the founders of the American Ornithologists Union and served as its president.
Coues' book A Key to North American Birds first edition was published in 1972. The book was at the time a unique work of ornithology, one which for years other guides to animal species would follow. Other important works by Coues included A Checklist of North American Birds (two editions) and Field Ornithology. Coues identified for the first time many unknown bird species and introduced the trinomial nomenclature used to distinguish subspecies of animals. All living species are known by their scientific name composed of Latin genus and species names. Coues introduced using a third Latin name for subspecies. Coues was also important in mammology, publishing North American Fur Bearing Animals in 1877.
Coues died on December 25, 1899 at Johns Hopkins University Hospital in Baltimore, Maryland, during an operation to cure an afflicted throat.
Allen, A.J.; "Biographical Memoir of Elliot Coues: 1842-1889"; in Biographical Memoirs Vol 6; National Academy Press; 1909
Anonymous; "A Great Ornithologist"; The Outlook(1900)64:89-90
Elliot, D.G.; "In Memoriam: Elliot Coues"; The Auk(1901)18:1-11
Elliot Coues Wikipedia Entry
Sunday, September 2, 2012
In 1887 he served as an unpaid lecturer at the University of Tartu. Four years later he became a professor of chemistry at Riga Polytechnic University and six years after that be became professor of physical chemistry at Lepzig University. Ostwald remained at Lepzig until his retirement in 1906, except for one year as the first exchange professor at Harvard University in 1904-5. Ostward's lab became a center for instruction in physical chemistry and among his students were many Nobel Prize winners including Arrhenius, Van 't Hoff and Nernst. Albert Einstein applied to work in Ostwald's lab.
Ostwald began his research in 1875 studying the law of mass action of water with the problem of chemical affinity and with special emphasis on electrochemistry. This led to the discovery of the law of dilution, which is named after him and governs the disassociation of a weak acid or base. Ostwald became one of the founders of modern physical chemistry and wrote several textbooks on the subject. Ostwald founded Zeitschrift fur physikalsche Chemie in 1887 and remained its editor until 1922 editing over 100 volumes. He is the inventor of the Ostwald process for producing nitric acid, which he patented in 1902. His development of the mole concept (a mole of a chemical being equal to its atomic mass in grams) was ironically part of his resistance to atomic theory, against which he was one of the last holdouts.
Ostwald won the 1909 Nobel Prize "in recognition for his investigations into the fundamental principals governing chemical equilibria and rates of reaction". Besides chemistry Ostwald had many insterests including philosophy and painting, for which he produced his own pigments. Later in his career he wrote several books dealing with color theory.
Ostwald died on April 4, 1932.
Kim, Mi Gyung; "Wilhelm Ostwald (1853-1932)"; 2006; at hyle.org
May, Leopold; "Wilhelm Ostwald"; 2003; at faculty.cua.edu
Wilhelm Ostwald Nobel Biography
Wilhelm Ostwald Wikipedia Entry