At least once each quarter and as much oftener as it deems necessary, the board of public welfare, as a body or by committee, shall visit and inspect the county hospital, the county infirmary or relief home for the aged, and the county jail. As often as it deems proper, or as it is directed by the board of supervisors or by a judge of the superior court, the board shall visit and inspect, in like manner, each jail or lockup in the county, and any charitable or correctional institution in the county, which receives any support from county funds. It shall examine every department of each institution visited and shall ascertain its condition as to effective and economical administration, and the cleanliness, discipline, and comfort of its inmates. It shall carefully study the rules prescribed by the board of supervisors for the control of each county institution, and the suggestions offered by the state departments having jurisdiction over the respective institutions, and shall ascertain whether or not such rules are being complied with.