Voluntarily causing hurt
321.  Whoever does any act with the intention of thereby causing hurt to any person, or with the knowledge that he is likely thereby to cause hurt to any person, and does thereby cause hurt to any person, is said “voluntarily to cause hurt”.
Voluntarily causing grievous hurt
322.  Whoever voluntarily causes hurt, if the hurt which he intends to cause or knows himself to be likely to cause is grievous hurt, and if the hurt which he causes is grievous hurt, is said “voluntarily to cause grievous hurt”.
     Explanation.— A person is not said voluntarily to cause grievous hurt except when he both causes grievous hurt and intends or knows himself to be likely to cause grievous hurt. But he is said voluntarily to cause grievous hurt if, intending or knowing himself to be likely to cause grievous hurt of one kind, he actually causes grievous hurt of another kind.
Illustration
     A, intending or knowing himself to be likely permanently to disfigure Z’s face, gives Z a blow which does not permanently disfigure Z’s face but which causes Z to suffer severe bodily pain for the space of 20 days. A has voluntarily caused grievous hurt.