Section 12
[Provided that where any part of such portion of the salary as is liable to attachment has been under attachment, whether continuously or intermittently, for a total period of twenty-four months, such portion shall be exempt from attachment until the expiry of a further period of twelve months, and, where such attachment has been made in execution of one and the same decree, shall, after the attachment has continued for a total period of twenty-four months, be finally exempt from attachment in execution of that deeree.]]