
Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1918
1920-1925
1952-3
1830 (original); 1967 (model)
circa 1919
1915-1925
1919
1928
1923
1923
1927
1917
1926
1915-1918
1920
1921-1931
1914-1916
1913
1927
circa 1915
1915-1918
1668; 1924
1930
1610; 1923
circa 1923
circa 1925
1926
1927
1915
1920
1915
1924
circa 1930
1918
1914-1920
1920-1929
1922
1932
1915-1917
1913-1923
1916
1921
1914
1924
1926
1931
1931
1931
1915