The parent, guardian, or legal or actual custodian of a child who is of compulsory attendance age, who is physically or mentally unable to attend school, or whose presence in school would be injurious to the health of other pupils, shall furnish proofs by certificate under sections 256B.6 and 256B.7 as to the physical or mental condition of the child.
88 Acts, ch 1259, §5; 91 Acts, ch 200, §8