"Invalid" means one who is physically or mentally incapacitated from earning.
[ 1961 c 23 s 51.08.110. Prior: 1957 c 70 s 13; prior: 1939 c 41 s 2, part; 1929 c 132 s 1, part; 1927 c 310 s 2, part; 1921 c 182 s 2, part; 1919 c 131 s 2, part; 1917 c 120 s 1, part; 1911 c 74 s 3, part; RRS s 7675, part.]