
Obsidian possibly used in trephination experiments
1918-1920
1918-1920
1917
1919
circa 1915
circa 1920
1915
1920
1915
1918
1916
1915
1915
1917
1918
1955; 1830
1915-1917
1918
1918
1915-1918
1916-1917
1921
1920
2000-100 BCE
circa 1920
1922
1915
1920
1917-1918
1915
1921
1934
1920
1920
1920
1903 (original); 1982 (model)
1772 (original); 1919 (model)
1990-96
circa 1920
1830 (original); 1967 (model)
1952-3
circa 1920
1839 (original); circa 1988 (replica)
1915-1916
1917-1918
circa 1917
1922
1915-1918
circa 1919
1918-1920
1915