persons eligible to the vacant place.

(_b_) If fitness for the vacant place is tested by competitive
examination, the names of the three eligibles highest in grade on the
proper register who have not been three times certified shall be
certified; but if the request indicates the sex of the eligibles desired
the three highest in grade of that sex shall be certified: _Provided_,
That the eligibles upon any register who have been allowed preference
under section 1754 of the Revised Statutes shall be certified,
according to their grade, before all other eligibles thereon:
_Provided further_, That no certification for an appointment shall
be made under this clause while there are persons in the district in
which any vacancy may exist, who have been removed from the service in
that district on account of a reduction of the force or otherwise, who
are eligible for reinstatement under Internal-Revenue Rule VII, and who
are willing to reenter the service by reinstatement. Every collector of
internal revenue shall keep a list of all such persons in his office,
and said persons shall have preference for reinstatement to the service
in the order of their separation therefrom.

(_c_) No eligible shall be certified more than three times.

2. Of the three names certified to him the Commissioner of Internal
Revenue shall select one, and may select more than one if more than one
vacancy exists at the time the certification is made. If the vacancy is
in the class of clerk, the Commissioner shall certify the name of the
person selected by him to the collector of the district in which the
vacancy occurs and the collector shall make the appointment. If the
vacancy is in the storekeepers', gaugers', or storekeepers and gaugers'
class, the Commissioner of Internal Revenue shall certify the name to
the Secretary of the Treasury with his recommendation that the person
whose name is thus certified be appointed: _Provided_, That if any
objection is made under section 3 of General Rule IV to any eligible
certified, and is sustained by the Commission, another eligible shall
be certified in the place of the one objected to.

3. Each person thus selected for appointment shall be notified, and upon
indicating his acceptance shall be appointed for a probationary period
of six months, at the end of which period, if his conduct and capacity
be satisfactory to the appointing officer