1868-1938

German biologist who made landmark contributions to the development of histology and cell theory. Schwann's studies of yeast fermentation provided evidence against the doctrine of spontaneous generation and led to progress in understanding cellular metabolism. His studies of the notochord led him to propose that the nucleated entities he had observed were the animal counterparts of the plant cells that had been studied by M. J. Schleiden (1804-1881). Schwann concluded that plants and animals were composed of cells and cell products.