49. Any person subject to this Act who commits any of the following offences, that is to say:-(a) when in command of a guard, piquet, patrol or post, releases without proper authority, whether wilfully or without reasonable excuse any person committed to his charge or refuses to receive any prisoner or person so committed; or(b) wilfully or without reasonable excuse allows to escape any person who is committed to his charge, or whom it is his duty to keep or guard;shall, on conviction by court-martial, be liable, if he has acted wilfully, to suffer long imprisonment; and if he has not acted wilfully, to suffer short imprisonment.