After three years of study and practice in the Sanitarium she applied for admission to the Woman's Medical College in Philadelphia, from which she was graduated in the spring of 1869. She often spoke of the pleasure she had in lingering in the park after class hours, on her way to her boarding-place, and of the occasional free and intimate talks with certain of her instructors.

She enjoyed the Sabbath services and had many opportunities of hearing some of the celebrated preachers of the day. The Rev. Dana Boardman seems to have been a favorite with her and she took notes of several of his sermons. "Bishop Simpson's Christmas sermon (1868) on Luke 2:13, 14, filled my heart with peace and good-will to (all) men," she notes. A sermon by Dr. Willett in November, 1868, on "What do ye more than others?" -- Matt.5:47, and one by Dr. McGowan on Mark 10:21, "One thing thou lackest," led to much heart-searching. A short time before leaving Philadelphia she heard Phillips Brooks preach from Malachi 4:2. "A wonderful sermon," she termed it, and she greatly enjoyed a talk by him on tithing, which she determined to act upon.

We have no special record of Dr. Swain's years of study in the Woman's Medical College, but we may be sure that she improved every opportunity to perfect herself in her chosen calling. Her instructors were her warm friends and she corresponded with some of them after she went to India. Dean Bodley, in one of her letters, gave the names of nine young women in the college who were preparing for medical missionary work, and Dr. Swain made a note of them, saying that she must write to them before their graduation. Two of these ladies went to India as medical missionaries.