§ 61. Subcommittees. Whenever any committee of either house or a joint committee of both houses of the legislature shall be required to make an inquiry or investigation, such committee may appoint a subcommittee of not less than three of its own members to make such inquiry or investigation, and to take testimony in relation thereto; and such committee or subcommittee and the chairman thereof shall respectively have all the powers and authority, which are conferred by law upon any committee which is authorized to send for persons or papers, or upon the chairman thereof. No subcommittee shall have the power to take testimony at a private hearing or at a public hearing unless at least two of its members are present at such hearing.