List of Famous people who died in 1921

Heinrich Wilhelm Gottfried von Waldeyer-Hartz was a German anatomist, known for summarizing neuron theory and for naming the chromosome. He is also remembered by anatomical structures of the human body which were named after him: Waldeyer's tonsillar ring and Waldeyer's glands.

Wilhelm Julius Foerster was a German astronomer. His name can also be written Förster, but is usually written "Foerster" even in most German sources where 'ö' is otherwise used in the text.

Oswald Schmiedeberg was a Baltic German pharmacologist. In 1866 he earned his medical doctorate from the University of Dorpat with a thesis concerning the measurement of chloroform in blood, before becoming the first professor of pharmacology at the University of Strasbourg, where he remained for 46 years.

Walter Morrison was an English Liberal and Liberal Unionist politician who sat in the House of Commons in three periods between 1861 and 1900. He was a major funder and the treasurer of the Palestine Exploration Fund; in later years the fund was dependent on his donations.

Max Noether was a German mathematician who worked on algebraic geometry and the theory of algebraic functions. He has been called "one of the finest mathematicians of the nineteenth century". He was the father of Emmy Noether.

Heinrich Emil Albert Knoevenagel was the German chemist who established the Knoevenagel condensation reaction. The Knoevenagel condensation reaction of benzaldehydes with nitroalkanes is a classic general method for the preparation of nitroalkenes, which are very valuable synthetic intermediates.

Konstantin Sergeevich Mereschkowski was a prominent Russian biologist and botanist, active mainly around Kazan, whose research on lichens led him to propose the theory of symbiogenesis – that larger, more complex cells evolved from the symbiotic relationship between less complex ones. He presented this theory in 1910, in his Russian work, The Theory of Two Plasms as the Basis of Symbiogenesis, a New Study of the Origins of Organisms, although the fundamentals of the idea already had appeared in his earlier 1905 work, The nature and origins of chromatophores in the plant kingdom.