
Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1919
1920-1925
circa 1920
1920
1924
1918
1920-1925
1918
1925
1924
1955; 1830
1918
1918
1922-1923
1922-1923
1922-1923
1922-1923
1921
1920
2000-100 BCE
circa 1920
1923
1925
1922
1920
1924
1921
1923
1934
1925
1920
1920
1920
1903 (original); 1982 (model)
1925
1772 (original); 1919 (model)
1990-96
circa 1920
1830 (original); 1967 (model)
1952-3
circa 1920
1839 (original); circa 1988 (replica)
1924
1922-1923
1922
1922-1924
circa 1919
1918-1920
4000-2001 BCE