Peter Hermann Stillmark

Peter Hermann Stillmark (22 July 1860 in Penza, Penza Oblast, Russia; 23 June 1923 in Pärnu, Estonia) was a Baltic-German microbiologist.

In 1888 at the University in Dorpat, now Tartu in Estonia under prof. Rudolf Kobert's supervision Peter Hermann Stillmark (1860–1923) completed his doctoral thesis "Über Ricin, ein giftiges Ferment aus den Samen von Ricinus comm. L. und einigen anderen Euphorbiaceen", which is a description of the isolation of ricin, a poisonous protein component from castor beans. That event is internationally recognised as the birth of a new branch of science called lectinology.

Any of a group of proteins, derived from plants, that can bind to specific oligosaccharides on the surface of cells, causing the cells to clump together. Lectins can be used to identify mutant cells in cell cultures and to determine blood groups as they can cause the agglutination of red blood cells. Lectins are found in seeds of legumes and in other tissues, in which they are thought to act as a toxin.