John Snow, Physician, reformer. During the cholera epidemics of the late 1840s and early 1850s, physician John Snow realized that cholera is transmitted through contaminated water. His essay, "On the Mode of Communication of Cholera" was fi...

Thomas Austin was an English settler in Australia who is generally noted for the introduction of rabbits into Australia in 1859. As a member of the Acclimatisation Society of Victoria, Thomas Austin helped to introduce many species from...

Sir Joseph Dalton Hooker was one of the greatest British botanists and explorers of the 19th century. Hooker was a founder of geographical botany, and Charles Darwin's closest friend. He was Director of the Royal Botanical Gardens, Kew, for...

Gregor Johann Mendel was a Austrian priest and scientist, and is often called the father of genetics for his study of the inheritance of traits in pea plants. Mendel showed that the inheritance of traits follows particular laws, which were...

Henry Walter Bates was an English naturalist and explorer who gave the first scientific account of mimicry in animals. He was most famous for his expedition to the rainforests of the Amazon with Alfred Russel Wallace, starting in 1848. Wall...

Paul Belloni du Chaillu was a French-American traveler and anthropologist. He became famous in the 1860s as the first modern outsider to confirm the existence of gorillas, and later the Pygmy people of central Africa. He later researched th...

Friedrich Leopold August Weismann was a German evolutionary biologist. Ernst Mayr ranked him the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute a...

John Muir was a Scottish-American naturalist, author, and early advocate of preservation of wilderness in the United States. His letters, essays, and books telling of his adventures in nature, especially in the Sierra Nevada mountains of Ca...

Henri Rousseau was a French Post-Impressionist painter in the Naïve or Primitive manner. He was also known as Le Douanier (the customs officer), a humorous description of his occupation as a toll collector. Ridiculed during his lifetime, he...

Sir Henry Alexander Wickham was a British explorer. He later claimed in publicity that he was responsible for stealing about 70,000 seeds from the rubber-bearing tree, Hevea brasiliensis, in the Santarém area of Brazil in 1876. However ther...

Daniel Elmer Salmon was a veterinary surgeon. He earned the first D.V.M. degree awarded in the United States, and spent his career studying animal diseases for the U.S. Department of Agriculture. He gave his name to the Salmonella genus of...

Karl Blossfeldt was a German photographer, sculptor, teacher and artist who worked in Berlin, Germany. He is best known for his close-up photographs of plants. He worked as an apprentice in an artistic form of iron casting at the iron found...

Scientist and early advocate for industrial uses for farm crops (bio-energy). Carver earned a B.S. from the Iowa Agricultural College in 1894 and an M.S. in 1896. He became a member of the faculty of Iowa State College and then Tuskegee Ins...

David Grandison Fairchild was an American botanist and plant explorer. Fairchild was responsible for the introduction of more than 200,000 exotic plants and varieties of established crops into the United States, including soybeans, pistachi...

Alice Hamilton was an American physician, research scientist, and author who is best known as a leading expert in the field of occupational health and a pioneer in the field of industrial toxicology. Subsequent to her graduation from the...