57.  (1) No person shall send by post any material or postal article which is likely to injure any person in the course of transmission by post.

(2) Except as otherwise provided by regulations made under this Act and subject to such conditions as may be prescribed, no person shall send by post any explosive, inflammable, dangerous, filthy, noxious or deleterious substance or any sharp instrument not properly protected which is likely to injure any person or any postal article in the course of transmission by post.