1834 births

Paul Camille Guigou (15 February 1834 – 21 December 1871) was a French landscape painter.
Guigou was born in Villars, Vaucluse in a wealthy family of farmers and notaries. He studied painting in Apt and later with Émile Loubon in Marseille. From 1854 to 1861, he worked as a notary clerk in Marseille. In 1863, after Loubon's death, he left Marseille for Paris, where he lived for most of his life. He frequented Café Guerbois, a regular location of many future impressionist painters.
Guigou painted mostly Provence landscapes using oil and watercolour. His early art was influenced by Loubon, and later by the Barbizon school and Gustave Courbet. He did not gain widespread recognition during his lifetime, and was often met with indifference at public exhibitions. Unable to survive financially from his own paintings, he also worked as an art tutor and critic.
He died in Paris at the age of 37 from a stroke. After his death, his pieces generally fell from the public eye for around thirty years until the Centennial Exposition of French Art in 1900, where he was rediscovered. His paintings can be found on public display in Paris and Marseille.

Claude Ferdinand Gaillard (7 January 1834 – 19 January 1887) was a French engraver and painter, who had been born and died in Paris.

Auguste Gabriel Maurice Raynaud (10 August 1834 – 29 June 1881) was the French medical doctor who discovered Raynaud syndrome, a vasospastic disorder which contracts blood vessels in extremities and is the "R" in the CREST syndrome acronym, in the late 19th century.

Felix Ludwig Julius Dahn (9 February 1834 – 3 January 1912) was a German law professor and nationalist author, poet and historian.

Gustav Nachtigal (German: [ˈɡʊstaf ˈnaxtɪɡal]; born 23 February 1834 – 20 April 1885) was a German military surgeon and explorer of Central and West Africa. He is further known as the German Empire's consul-general for Tunisia and Commissioner for West Africa. His mission as commissioner resulted in Togoland and Kamerun becoming the first colonies of a German colonial empire. The Gustav-Nachtigal-Medal, awarded by the Berlin Geographical Society, is named after him.

August Friedrich Leopold Weismann FRS (For), HonFRSE, LLD (17 January 1834 – 5 November 1914) was a German evolutionary biologist. Fellow German Ernst Mayr ranked him as the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg.
His main contribution involved germ plasm theory, at one time also known as Weismannism, according to which inheritance (in a multicellular animal) only takes place by means of the germ cells—the gametes such as egg cells and sperm cells. Other cells of the body—somatic cells—do not function as agents of heredity. The effect is one-way: germ cells produce somatic cells and are not affected by anything the somatic cells learn or therefore any ability an individual acquires during its life. Genetic information cannot pass from soma to germ plasm and on to the next generation. Biologists refer to this concept as the Weismann barrier. This idea, if true, rules out the inheritance of acquired characteristics as proposed by Jean-Baptiste Lamarck. However, a careful reading of Weismann's work over the span of his entire career shows that he had more nuanced views, insisting, like Darwin, that a variable environment was necessary to cause variation in the hereditary material.The idea of the Weismann barrier is central to the modern synthesis of the early 20th century, though scholars do not express it today in the same terms. In Weismann's opinion the largely random process of mutation, which must occur in the gametes (or stem cells that make them) is the only source of change for natural selection to work on. Weismann became one of the first biologists to deny Lamarckism entirely. Weismann's ideas preceded the rediscovery of Gregor Mendel's work, and though Weismann was cagey about accepting Mendelism, younger workers soon made the connection.
Weismann is much admired today. Ernst Mayr judged him to be the most important evolutionary thinker between Darwin and the evolutionary synthesis around 1930–1940, and "one of the great biologists of all time".

Edmond Nicolas Laguerre (9 April 1834, Bar-le-Duc – 14 August 1886, Bar-le-Duc) was a French mathematician and a member of the Académie des sciences (1885). His main works were in the areas of geometry and complex analysis. He also investigated orthogonal polynomials (see Laguerre polynomials). Laguerre's method is a root-finding algorithm tailored to polynomials. He laid the foundations of a geometry of oriented spheres (Laguerre geometry and Laguerre plane), including the Laguerre transformation or transformation by reciprocal directions.

Frank Richard Stockton (April 5, 1834 – April 20, 1902) was an American writer and humorist, best known today for a series of innovative children's fairy tales that were widely popular during the last decades of the 19th century.