In addition to Rosenow, Wintrobe and Tavassoli, the german hematologist Günther Brittinger and Herbert Neumann (see button rediscovery) considered Ernst Neumann as one of the famest hematologists in the 19.th century (see button Ernst Neumann, Cytology and Rediscovery).

History of the Stem cell 1868 - 1914 Koenigsberg/ Prussia

E. Neumann described 1868/69 the origin cell of the red blood corpuscles (the later "great lymphocytic stem cell" (see below 1912) and called herself "Lymphoid marrow cell" (Blood and Pigments (BP), S.33).
 "It is evident, that a continuing transformation lymphoid cells into coloured blood cells" takes place in the bone marrow during the whole life"   1869, BP.S. 19.

This "Lympoid marrow cell" forms not only the erythrocytopoiesis but it is capable (in itself) to self regeneration. 1869, BP. Side 30 - 34 . “In order of the size differences of the lymphoid marrow-cells, we will be right  in thinking that a permanent fluctuation will take place in the bone marrow" (BP p. 30).

1912: Until 1912 Neumann called the stem cell "lymphocyte", "great lymphocyte" or "Lymphomyeloblast". Since that time,  he declares:
The different forms of all blood cells happening in the blood, the lymph-organums and in the bone marrow are all descendants of the great-lymphocytic stem cell. (BP, page 313). In which way this stem cell completes itself again and again, whether exclusively by a mitotic division or also from other cells particularly from cells of the mesenteric tissue, may be discussed.

Neumann was advocate of the Unitarien Point of View: All blood cells shall be descended from this post embryonic stem cell. 

As it is well known, a quarrel broke out between dualists and unitarians (P. Ehrlich). Neumann's farsightedness demanded a stem cell culture for the completion of the quarrel:

"Perhaps a final decision will only arrive, if it possible, to isolate the individual colourless cells and to study its life events in vitro culture  for some time, as Robert Koch  demonstrated with the bacteria"  (N 118, 1912, BP, p. 299).

This passage earned a great mention in the book of H. Neumann and Y. Klinger - see below

1914 Where does the stem cell comes from? Neumann answered:  "We have the right, to think that the stem cells in the bone marrow are descended of the Reticulum-cells ." N 119, 1914, BP, p. 362
The original text of Neumanns meaning see http://www.gelehrtenfamilie-koenigsberg.net -page History of stem-cell

Literatur:

Neumann, E.: Blut und Pigmente. Jena Gustav Fischer 1917

Tavassoli, M.; Yoffey, J.M. : Bone Marrow; Structure and Function. Alan R.Liss, Inc., 1983 New York
Wintrobe, M. : Hematology, the Blossoming of a Science; a Story of Inspiration and Effort. Lea & Febiger Philadelphia 1985
Schinck, Peter: Ernst Neumann als Begründer der Hämatologie, Dissertation am Pathologischen
Institut in Königsberg (Prof. Kaiserling) 1920
Neumann-Redlin von Meding, E.: Der Pathologe Ernst Neumann (1834 -1918) und sein Beitrag
zur Begründung der Hämatologie im 19.Jahrhundert, Demeter Verlag 1987.
Klinger, Y. Über die Entdeckung der hämatopoetischen Funktion des Knochenmarks und das
Postulat der Stammzelle. Dissertation aus der Medizinischen Klinik der Ruhr-Universität
Bochum 1992:
H. Neumann, H., Klinger, Y.: Knochenmark und Stammzelle – Der Kampf um die Grundlagen
der Hämatologie Blackwell Wissenschaft, Ex libris Roche Bd. 1 1994

Zech,N.H., Shkumatov,A. Koestenbauer,S.: Die magic behind stem cells. Journal of Assisted Reproduction and Genetics Vo. 24, Nr. 6 (2007) 208 - 214