void monster_adjustment::apply( mtype &mon )
{
    if( !mon.in_species( species ) ) {
        return;
    }
    if( !stat.empty() ) {
        if( stat == "speed" ) {
            mon.speed *= stat_adjust;
        } else if( stat == "hp" ) {
            mon.hp *= stat_adjust;
        }
    }
    if( !flag.empty() ) {
        mon.set_flag( io::string_to_enum<m_flag>( flag ), flag_val );
    }
    if( !special.empty() ) {
        if( special == "nightvision" ) {
            mon.vision_night = mon.vision_day;
        }
    }
}