In April, 1862, she became satisfied that she could be more useful in the field, by taking good nurses to the army hospitals, and herself laboring with them. Her husband, who the previous winter had been commissioned as Chaplain of the First Illinois Light Artillery, was then at Cairo, where he had been ordered to labor in hospitals; and Mrs. Porter, visiting Cairo and Paducah, entered earnestly into the work of placing the nurses she had brought with her from Chicago. Some of these devoted themselves constantly to the service, and proved equally successful and valuable. At Cairo, Mrs. Porter made the acquaintance of Miss Mary J. Safford, since known as the "Cairo Angel," and co-operating with her there, and with Mr. Porter and various surgeons and philanthropists, aided in receiving, and temporarily caring for seven hundred men from the field of Pittsburgh Landing, and in transferring them to the hospitals of Mound City, Illinois. From four o'clock in the morning until ten at night, Mrs. Porter and her friends labored, and then, their work accomplished and their suffering charges made as comfortable as circumstances would permit, they were forced, by the absence of hotel accommodations, to spend the night upon the steamer where the state-rooms being occupied, they slept upon chairs. Soon afterward she went, accompanied by Miss Safford, to Pittsburgh Landing. There she obtained from the Medical Director, Dr. Charles McDougal, an order for several female nurses for his department. She hastened to Chicago, secured them, and accompanying them to Tennessee placed them at Savannah with Mrs. Mary Bickerdyke, who had been with the wounded since the battle of Shiloh. From thence she went to Corinth, then just taken by General Grant. She was accompanied by several benevolent ladies from Chicago, like herself bent on doing good to the sick and wounded. At Corinth she joined her husband, and he being ordered to join his regiment at Memphis, she went thither in his company. Here, principally in the hospital of the First Light Artillery at Fort Pickering, she labored through the summer of 1862, and afterwards returned to visit some of the southern towns of Illinois in search of stores from the farmers, which she added to the supplies forwarded by the Commission. While at Memphis, Mrs. Porter became deeply interested in the welfare of the escaped slaves and their families congregated there. Receiving aid from friends at the North, she organized a school for them, and spent all her leisure hours in giving them instruction. One of the nurses she had brought thither desired to aid in the work, and obtaining needful books and charts she organized a school for Miss Humphrey at Shiloh. Mrs. Porter was very successful in this work. In her youth she had gathered an infant school among the half-breed children at Mackinac and Point St. Ignace, and understood well how to deal with these minds scarce awakened from the dense slumber of ignorance.