From the club's website:
Over the years many of the original golf clubs that lined City Avenue at one time succumbed to the pressure of the burgeoning city and relocated their entire Club to a more suburban locale. Prestigious Philadelphia Country Club was originally located on the site of the old Adam's Mark Hotel. In fact, when they moved to their new home in Gladwyne in 1939, Bala Golf Club "inherited" many of their greens and they are still being used today by our Members.
That site, laid out by Willie Tucker, provided the club members with a 9 hole, 2,747 yard layout with a par of 35 1/2. Although the original course was higly regarded, the pressure to go to an 18 hole course convinced the membership to act, and, in 1923, William S. Flynn, a noted golf course designer (among them, Rolling Green, Huntington Valley, Cherry Hills in Denver, The Country Club in Brookline, Seaview, Shinnecock Hills, and Lancaster CC), was brought in to renovate the course. Flynn's challenge was to build nine additional holes, fold them into the Tyler design, and fit it all into the existing acreage. He succeeded admirably.