An instructive article on "The Progress of the Negro Race" was prepared for the _Edinburgh_ of January, 1864. Only a few weeks after the appearance of this, there fell upon her the greatest blow of her old age. Her beloved niece Maria, who had for so long filled the place of a daughter to her, was taken ill with typhoid fever, and died after a three weeks' illness. Maria Martineau's active disposition, and her intellectual power (which was far above the average) had made her an ideal companion for her aunt, and the blow to _her_ was a terrible one. Ill and suffering as she was before, this shock completed the wreck of Harriet Martineau's health. She had a dreary time of illness immediately after her niece's death; and although she went on writing for some time longer, it was always with the feeling that the end of her long life's industry was near at hand. She was not left alone; for Maria's youngest sister, Jane, presently offered voluntarily to fill, as far as she could, the vacant place at "The Knoll." The family from which these sisters came was one in which kindliness and generosity were (and are to this day, with its younger members who remain) distinguishing features. It was no light matter for Mr. and Mrs. Robert Martineau to part with a second daughter to their sister; but, as it was Jane's own wish to try to be to that beloved and honored relative what Maria had been, the parents would not refuse their permission. Harriet wrote of this to Mr. Reeve with her heart full; telling him how "humbly grateful" she felt for what was so generously offered to her, and with what thankfulness she accepted the blessing. Even in such circumstances, she could note what a delight it was to find that Maria's own spirit of devotedness prevailed amongst them all--for nothing could be nobler and sweeter than the conduct of everyone. By June of that same year, 1864, Mrs. Martineau was ready to undertake another article on a topic which pressed upon her mind, "Co-operative Societies," which was published in the _Edinburgh_ for October following. She went on writing for the _Daily News_, through that year and the next, though the effort came to be constantly more and more laborious. Her interest in public affairs did not flag; nor is there the least sign of failure of power in her letters; but she became increasingly conscious that it was a strain upon her to write under the responsibility of addressing the public.