The story of Dr. Swain's call to go to India has been told many times. Mrs. D.W. Thomas, who, with her husband, had charge of the girls' orphanage of the Methodist Mission, had long felt the need of efficient medical aid for the women and children of India and had been doing what she could to alleviate the sufferings of those with whom she came in contact. She had even thought that she would herself study medicine when she should go to America for change and rest. In the meantime she was instructing a class of the older girls in the orphanage in physiology and hygiene, both in English and the vernacular, with the hope that some time they might have regular medical training. She talked with native gentlemen and with English officials of the great need for intelligent medical treatment for the women and children of the country, especially for those who live in seclusion, and of her hope that a lady medical missionary might be sent to India. A native gentleman so thoroughly approved of the idea that he offered to defray all the expenses of a medical school or class if a lady physician could be sent from America to take charge of it.

Mrs. Thomas's letter of appeal to Mrs. J.T. Gracey, a former missionary, for her assistance in the matter, led Mrs. Gracey to inquire at the Philadelphia Woman's Medical College if a suitable person could be found among the graduates, who would accept a call from the Woman's Union Missionary Society of America to go as a medical missionary to India. Miss Clara A. Swain, M.D., was named as one fitted by both professional acquirements and Christian character for such a position. It required much thought and prayer on Dr. Swain's part before she could signify her acceptance of the call, and during the three months of delay in giving her answer the Woman's Foreign Missionary Society of the Methodist Episcopal Church, of which she was a member, was organized. Naturally she preferred to go under the auspices of her own denomination, and the Union Missionary Society gracefully and generously accepted her decision.

Confident that she was obeying the call of God, she set about her preparations for the long journey before her in a cheerful spirit, answering the demurs of her friends with, "It is God's call. I must go." She was greatly cheered when she found that Miss Isabella Thoburn, whose brother (now Bishop Thoburn) had been some years in India, was to be her traveling companion. They sailed from New York November 3, 1869, and arrived in Bareilly January 20, 1870, during the annual conference of the Methodist Mission.