In most of the great political and ecclesiastical controversies of his day, Dr. Anderson has stood forward as the unflinching champion of justice and mercy. He was a prominent and effective speaker on the Voluntary question; and he rendered effective service to the movement for the repeal of the slave trade. Besides these pet themes, Dr. Anderson has always been a vigorous assailant of Popery, on which he has spoken perhaps more frequently, and with greater effect, than any other man of his time. During his crusade against Popery he received an anonymous letter threatening that if he proceeded with his lectures on the subject of the Mass, his life would be in danger. Nothing daunted, however, he sent the anonymous letter to the head of the Roman Catholic Church in Glasgow, with the intimation that it was still his intention to persevere with his lectures despite threats and cajolery. About this time he challenged to a public discussion the well-known Dr. Cahill, who was then regarded as the champion of the Romish Church in this country. His challenge was respectfully declined; but so bitter was the _animus_ raised against him that on more than one occasion he had to be escorted to the platform of the City Hall by policemen. Finally, he overcame the opposition of the Papists so far as to secure a patient hearing, and it has since been admitted that his lectures were greatly instrumental in arousing public opinion to a just sense of the errors and insidious influence of the priests and the Papacy. There are, doubtless, not a few still living in Glasgow who will remember Dr. Anderson's scathing denunciations of American slavery and the strong sympathy which, from the outbreak of the civil war, he expressed with the Federals. When Henry Ward Beecher visited and lectured in Glasgow, he was supported by Dr. Anderson, who spoke so bitterly and with such emphatic disapprobation against the Southern States and their policy, that his sentiments evoked the hisses of his audience. Nothing discomfited, he pursued the even tenor of his way, until he reached the climax of his argument, when bearing down upon his opponents with irresistible force, he cried out, in a voice of triumph, "Hiss, noo, gin ye dare." On that occasion he created a profound impression by his eloquent appeal to Mr. Ward Beecher to interpose with his countrymen to avert from Britain the consequences which her sympathies for the slave-holding States had justly entailed.