By June 1864, the staff was caring for as many as 119 patients at one time, most of who were wounded soldiers. This brought about a building program that added the East Wing in early in 1865. Until that time patients were housed anywhere there was space, in the dome, even in tents on the lawn. The reception room doubled as a patient library and operating room. There was no laboratory, or nursing school. City water, drawn from nearby wells, was transported in barrels.
The Hospital continued to grow, adding the West Wing in 1871. This wing incorporated a third floor under a mansard roof that housed private rooms for "private pay" patients. The private rooms incorporated all the amenities of home. By the 1870's it was discovered that some members of the growing middle class were willing to come to the hospital as patients.
In 1872 the medical staff organized, with four physicians and four surgeons. Dr. Harvey Montgomery was its first President.