
Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1918
1952-3
1830 (original); 1967 (model)
circa 1919
1919
1911
1917
1915-1918
1920
1914-1916
1909-1910
1913
circa 1915
1915-1918
1668; 1924
1610; 1923
1907
1910
1915
1920
1915
1910
1908
1918
circa 1910
1914-1920
1909
1910
1922
1915-1917
1907-1920
1916
1921
1914
1915
1912
1915
1910
1917
1910
1918
1912
1915
1921
1915
1910-1920
circa 1920
1914-1918
1955; 1830