-
Red Blood Cell / Erythrocytes
Jan Swammerdam observed red blood cells under a microscope. -
Robert Hooke
described a honeycomb-like network of cellulae in cork slice using his primitive compound microscope. Robert Hooke used the term cells to describe units in plant tissue (thick cell walls could be observed). Of course he saw only cell walls because cork cells are dead and without protoplasm. He drew the cells he saw and also coined the word cell. The word cell is derived from the latin word cellula which means small compartment. -
Antonie van Leeuwenhoek
Antonie van Leeuwenhoek (1632-1723) described cells in a drop of pond water using a microscope. A Dutch businessman and a contemporary of Hooke. He also used microscopes and was a physicist. He made his own fine quality lens for use in monocular microscopes and was the first person to observe bacteria and protozoa. Some of his lenses could magnify objects 250X. -
Protozoa
Anton van Leeuwenhoek observed protozoa and calls them animalcules. -
Spermatozoa
Anton van Leeuwenhoek observed spermatozoa. -
Jan Ingenhousz
Jan Ingenhousz, (born Dec. 8, 1730, Breda, Neth.—died Sept. 7, 1799, Bowood, Wiltshire, Eng.), Dutch-born British physician and scientist who is best known for his discovery of the process of photosynthesis, by which green plants in sunlight absorb carbon dioxide and release oxygen. -
Amoeba
The earliest record of an amoeboid organism was produced in 1755 by August Johann Rösel von Rosenhof, who named his discovery "Der Kleine Proteus" ("the Little Proteus"). Rösel's illustrations show an unidentifiable freshwater amoeba, similar in appearance to the common species now known as Amoeba proteus. -
Tissues of a Developing Chick
Kaspar Friedrich Wolff argued that the tissues of a developing chick form from nothing and are not simply elaborations of already-present structures in the egg. -
Disproving of Spontaneous Generation
Lazzaro Spallanzani again disproved spontaneous generation by showing that no organisms grow in a rich broth if it is first heated (to kill any organisms) and allowed to cool in a stoppered flask. He also showed that fertilization in mammals requires an egg and semen -
Plants and Gas
Joseph Priestley demonstrated that plants produce a gas that animals and flames consume. Those two gases are carbon dioxide and oxygen. -
Cancer
The first cause of cancer was identified by British surgeon Percivall Pott, who discovered in 1775 that cancer of the scrotum was a common disease among chimney sweeps. The work of other individual physicians led to various insights, but when physicians started working together they could draw firmer conclusions. -
Modern theory of evolution
Lamarck proposed a modern theory of evolution based on the inheritance of acquired characteristics -
Robert Brown
English Botanist Robert Brown discovered the nucleus in plant cells. -
Matthias Jakob Schleiden
concluded that all plant tissues are composed of cells and that an embryonic plant arose from a single cell. He declared that the cell is the basic building block of all plant matter. This statement of Schleiden was the first generalizations concerning cells. -
Theodor Schwann,
a German biologist, reached the same conclusion as Schleiden about animal tissue being composed of cells, ending speculations that plants and animals were fundamentally different in structure. Schwann described cellular strucures in animal cartilage (rigid extracellular matrix). He pulled existing observations together into theory that stated 1. Cells are organisms and all organisms consist of one or more cells. 2. The cell is the basic unit of structure for all organisms. -
Fermentation
Louis Pasteur stated that microorganisms produce fermentation. -
Theory of Biological Evolution
Charles R. Darwin and Alfred Wallace independently proposed a theory of biological evolution ("descent through modification") by means of natural selection. Only in later editions of his works did Darwin used the term "evolution." -
Louis Pasteur
introduced the terms aerobic and anaerobic in describing the growth of yeast at the expense of sugar in the presence or absence of oxygen. He observed that more alcohol was produced in the absence of oxygen when sugar is fermented, which is now termed the Pasteur effect. -
Nucleic Acid
Friedrich Miescher discovered nucleic acids in the nuclei of cells. -
Thomas H. Huxley
Thomas H. Huxley's Biogenesis and Abiogenesis address is the first clear statement of the basic outlines of modern Darwinian science on the question of the origin of life. The terms "biogenesis" (for life only from pre-existing life) and "abiogenesis" (for life from nonliving materials, what had previously been called spontaneous generation) as used by Huxley in this speech have become the standard terms for discussing the subject of how life originates. -
Ferdinand J. Cohn
Ferdinand J. Cohn contributes to the founding of the science of bacteriology. In the publication Ueber Bakterien, he discusses the role of microorganisms in the cycling of elements in nature. In 1875, Cohn will publish an early classification of bacteria, using the genus name, Bacillus, for the first time. -
Julius Oscar Brefeld
reported growing fungal colonies from single spores on gelatin surfaces. Prior to this innovation that resulted in the isolation of pure culture of microorganisms, pigmented bacterial colonies were isolated by the German biologist Schroeter on slices of potato incubated in a moist environment. -
Gerhard Henrik Armauer Hansen
described how he observed the leprosy bacillus, Mycobacterium leprae, as "rod-like bodies" after cutting through a leprosy nodule, scraping the edge of the cut with a knife and rubbing the material onto a glass slide. Armauer Hansen clearly demonstrated that these rods represented the infectious origin of leprosy. This is the first time that a chronic infectious disease in humans was shown to be related to a bacillus. -
Robert Koch
publishes a paper on his work with anthrax, pointing explicitly to a bacterium as the cause of this disease. This validates the germ theory of disease. Prior, in 1872, he was approved as a district medical officer in Poland where he discovered anthrax was endemic. His work on anthrax was presented and his papers on the subject were published under the auspices of Ferdinand Cohn. -
Jean Jacques Theophile Schloesing
proves that nitrification is a biological process in the soil by using chloroform vapors to inhibit the production of nitrate. One of the greatest practical applications of this knowledge was in the treatment of sewerage. -
Robert Koch
dries films of bacteria, stains them with methylene blue and then photographs them. He uses cover slips to prepare permanent visual records. -
John Tyndall
publishes his method for fractional sterilization and clarifies the role of heat resistant factors (spores) in putrefaction. Tyndall's conclusion adds a final footnote to the work of Pasteur and others in proving that spontaneous generation is impossible. -
Thomas Burrill
demonstrates for the first time a bacterial disease of plants; Micrococcus amylophorous causes pear blight. -
Joseph Lister
ublishes his study of lactic fermentation of milk, demonstrating the specific cause of milk souring. His research is conducted using the first method developed for isolating a pure culture of a bacterium, which he names Bacterium lactis. -
Neisseria gonorrhoeae
the pathogen that causes gonorrhea identified by Albert Neisser -
Mycobacterium tuberculosis
Robert Koch isolates the tubercule bacillus, Mycobacterium tuberculosis. The search for the tubercule bacillus is more difficult than was the search for the cause of anthrax. He finally isolates the bacillus from the tissues of a workman and stains them with methylene blue, yielding blue colored rods with bends and curves. He injects the tissues from people who had died into animals and then grows the bacilli he isolates into pure cultures. -
Corynebacterium diphtheriae
Edward Theodore Klebs and Fredrich Loeffler independently discover Corynebacterium diphtheriae, which causes diphtheria. Loeffler later shows that the bacterium secretes a soluble substance that affects organs beyond sites where there is physical evidence of the organism. -
Babesia microti
Theobald Smith and F.L. Kilbourne establish that ticks carry Babesia microti, which causes babesiosis in animals and humans. This is the first account of a zoonotic disease and also the foundation of all later work on the animal host and the arthropod vector. -
Open heart surgery
Black surgeon performs the first sucessful open-heart surgery in America. On this date in 1893, the first successful American open-heart surgery was performed by a Black surgeon, Dr. Daniel Hale Williams. Dr. Daniel Williams completed the operation on a young man named James Cornish. -
Glycolysis
The development of biochemistry and the delineation of glycolysis went hand in hand. A key discovery was made by Hans Buchner and Eduard Buchner in 1897, quite by accident. -
Sporotrichum schenckii
B. R. Schenck presents the first unequivocal case of sporotrichosis and includes a description of the organism that was first isolated from the patient. This organism was later named Sporotrichum schenckii. -
Genetics
William Bateson coined the term "genetics" to describe the study of biological inheritance. -
Francis Peyton Rous
Francis Peyton Rous discovers a virus that can cause cancer in chickens by injecting a cell free filtrate of tumors. This is the first experimental proof of an infectious etiologic agent of cancer. In 1909 a farmer brought Rous a hen that had a breast tumor. Rous performed an autopsy, extracted tumor cells and injected them in other hens, where sarcoma developed. Rous is awarded the Nobel Prize in Medicine or Physiology in 1966. -
bacteriophage
The first discovery of bacteriophage, by Frederick Twort. His discovery was something of an accident; he had spent several years growing viruses and noticed that the bacteria infecting his plates became transparent. -
Vibrio fetus
Theobald Smith and M. S. Taylor describe the microbe, Vibrio fetus n. sp., responsible for fetal membrane disease in cattle. -
Thomas Rivers
Thomas Rivers distinguishes between bacteria and viruses, establishing virology as a separate area of study. This paper was published after he presented it at an SAB meeting held in December of 1926. -
Frederick Griffith
Frederick Griffith discovers transformation in bacteria and establishes the foundation of molecular genetics. He shows that injecting mice with a mixture of live, avirulent, rough Streptococcus pneumoniae Type I and heat-killed, virulent smooth S. pneumoniae Type II, leads to the death of the mice. Live, virulent, smooth S. pneumoniae Type II are isolated from the dead mice. Not until the 1930's, did Avery, Macleod and McCarty take up Griffith's work and try to explain the results. -
Penicillin
The effects of penicillium mould would finally be isolated in 1928 by Scottish scientist Alexander Fleming, in work that seems to have been independent of those earlier observations. Fleming recounted that the date of his discovery of penicillin was on the morning of Friday 28 September 1928. -
Bacillus brevis
Rene Dubos working with Oswald Avery discovers Bacillus brevis, an organism that breaks down the capsular polysaccharide of Type III S. pneumocci and protects mice against pneumonia. -
Krebs Cycle
However, many people refer to the process as the Krebs cycle in recognition of the contribution of Hans Krebs to the discovery. Krebs, a German biochemist, first postulated the mechanism in 1937, under the name citric acid cycle. this process is named after Hans Adolf Kreb. -
streptomycin
Albert Schatz, E. Bugie, and Selman Waksman discover streptomycin, soon to be used against tuberculosis. Streptomycin has the same specific antibiotic effect against gram negative microorganisms as penicillin does on gram positives. Waksman is awarded the Nobel Prize in Medicine or Physiology in 1952. -
Discovery of DNA
The discovery in 1953 of the double helix, the twisted-ladder structure of deoxyribonucleic acid (DNA), by James Watson and Francis Crick marked a milestone in the history of science and gave rise to modern molecular biology, which is largely concerned with understanding how genes control the chemical processes within cells. -
Double-helix structure of DNA
James Watson and Francis Crick publish a description of the double-helix structure of DNA. The paper acknowledges that the authors were "stimulated by knowledge of the unpublished experimental results of" Maurice Wilkins and Rosalind Franklin, whose x-ray crystallography images of DNA suggested the structure. Franklin died in 1958; Watson, Crick and Wilkins are awarded the Nobel Prize in Physiology or Medicine in 1962. -
Interferon
Alick Isaacs and Jean Lindemann discover interferon, an antiviral protein produced by the body to fight viral infections. The first experiments take place with chick embryo tissue cultures infected with influenza virus. The interferon protects adjacent cells against the virus. -
Shuko Kinoshita, S.Udaka, and M. Shimono
discover that bacteria can be used to produce monosodium glutamate. This leads to a new industry; the microbial production of amino acids for human and animal nutrition as well as for food flavoring. -
Electron Transport Chain
American biochemist, Albert Lehninger, discovered that the citric acid cycle and the electron-transfer chain of enzymes (where 1 NADH makes 3 ATPs) are located within each cell's mitochondria. -
First Test Tube Baby
Born July 25, 1978, in Oldham, England. Louise Joy Brown is best known as the world's first "test-tube baby." Her birth by Caesarian section shortly before midnight on July 25, 1978, at Oldham General Hospital in England, made headlines around the world. -
HIV
Luc Montagnier and Robert Gallo announce their discovery of the immunodeficiency virus (HIV) believed to cause AIDS.
