[b. Frankfurt, Germany, January 17, 1834, d. Freiburg-im-Breisgau, Germany, November 5, 1914]

In a famous series of experiments in which he cut off the tails of mice for 22 generations, Weismann disproved the theory that acquired characteristics could be inherited. A strong proponent of Darwinian evolution, Weismann also proposed the germ plasm theory. This theory suggested that while the body, which Weismann called somatoplasm, lives for only one generation, hereditary material, which he called germ plasm, is immortal, passed from generation to generation without change.

History of Science and Technology, edited by Bryan Bunch and Alexander Hellemans. Copyright © 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.