
Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1918
1952-3
1830 (original); 1967 (model)
circa 1919
1919
1917
1915-1918
1920
1914-1916
1913
circa 1915
1915-1918
1668; 1924
1610; 1923
1915
1920
1915
1918
1914-1920
1915-1917
1916
1914
1915
1912
1915
1917
1918
1912
1915
1915
circa 1920
1914-1918
1955; 1830
1914
1914-1918
1918
1916-1917
c.1912
1914-1918
1914
2000-100 BCE
1917-1918
1914-1918
1914-1918
circa 1920
1914-1918
1920
1914
1914