The IPC 1860 was replaced by the BNS 2023 (in force 2024-07-01); no verified section mapping on file for Section 321 — confirm the corresponding provision (savings: Section 358, BNS 2023).
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".