BC1750The Sumerians brew beer.500 The Chinese use moldy soybean curds as an antibiotic to treat boils.250 The Greeks practice crop rotation to maximize soil fertility.100 Powdered chrysanthemum is used in China as an insecticide.AD: Before the 20th Century1590The microscope is invented by Janssen.1663 Cells are first described by Hooke.1675 Leeuwenhoek discovers protozoa and bacteria.1797 Jenner inoculates a child with a viral vaccine to protect him from smallpox.1802 The word "biology" first appears.1824 Dutrochet discovers that tissue is composed of living cells.1830 Proteins are discovered.1833 The cell nucleus is discovered.The first enzymes are isolated.1855 The Escherichia coli bacterium is discovered. It later becomes a major research, development, and production tool for biotechnology.Pasteur begins working with yeast, eventually proving they are living organisms.1863 Mendel, in his study of peas, discovers that traits were transmitted from parents to progeny by discrete, independent units, later called genes. His observations lay the groundwork for the field of genetics.1869 Miescher discovers DNA in the sperm of trout.1877 A technique for staining and identifying bacteria is developed by Koch.1878 The first centrifuge is developed by Laval.The term "microbe" is first used.1879 Flemming discovers chromatin, the rod-like structures inside the cell nucleus that later come to be called "chromosomes."1883 The first rabies vaccine is developed. 1888 The chromosome is discovered by Waldyer.AD: First Half of the 20th Century1902 The term "immunology" first appears.1906 The term "genetics" is introduced.1907 The first in vivo culture of animal cells is reported.1909 Genes are linked with hereditary disorders.1911 The fi...