The controversies which he had with some of his fellow-missionaries in China were a serious trial to him. He was not by inclination “a man of war,” but in connection with the prosecution of the missionary work in which he was engaged in common with his brethren, questions of great practical and immediate importance arose, and as to some of these he had strong convictions that were at variance with those of other wise and able men on the field. It was best for the cause that these should be thoroughly discussed, and there was much that could be fairly and earnestly urged upon either side. All that could be rightly demanded was that the “fighting” should be open and honorable, and that it should be conducted in such a manner as not to hinder the missionary work or to descend into personal controversy. Dr. Mateer, as to ability and efficiency, stood in the front rank of those who were giving their lives to the evangelization of China. It was his duty to express his views on these questions, and to do this in such a way that no one could misapprehend them. If any fault could be found with him in this matter, perhaps it would be that he saw his own side so vividly that he was not always able to recognize the entire force of that which was said in favor of what ran counter to it. Those who knew him well and appreciated the greatness and tenderness of his heart waived the sting which sometimes seemed to be in his words; but perhaps some others who were not so well acquainted with him occasionally winced under its pungency. Everyone who was concerned in these discussions, long ago has come to recognize him in these as an earnest, capable man, trying to do his duty as he saw it.