Mr. Sumner was at his lodgings, alone, on the fourth day after the speech, when, about six o’clock, P. M., he received a visit from a stranger, who opened conversation by saying that he was one of the class recently slandered, being a Southern man and a slaveholder, and that he had called for an explanation of the speech, and to hold its author responsible. A few words ensued, in which the visitor became still more offensive, when Mr. Sumner ordered him out of the room. After some delay, he left, saying, in violent tone, that he was one of four who had come from Virginia for the express purpose of holding Mr. Sumner responsible, and that he would call upon him again with his friends. Mr. Sumner sent at once to his colleague, Mr. Wilson, who quickly joined him. While they were together, a person came to the door who asked particularly to see Mr. Sumner alone, and when told that he was not alone, declined to enter. About nine o’clock in the evening three other persons came to the door, who asked to see Mr. Sumner alone, and receiving the same answer, they sent word by the domestic who opened the door, that Mr. ---- and two friends had called, but, not finding him alone, they would call again in the morning, for a private interview, and if they could not have it, they would cut his d----d throat before the next night. Such a message, with the attendant circumstances, put the friends of Mr. Sumner on their guard, and it was determined, contrary to his desire, that one or more should sleep in the house that night. Accordingly Hon. Anson Burlingame and Hon. John Sherman, both Representatives, slept in the room opening into his bedroom. In the morning other circumstances increased the suspicion that personal injury was intended. It was the desire of Mr. Sumner that this incident should be kept out of the newspapers; but it became known, and caused no small excitement at Washington, and through the country. It was the subject of telegrams and of letters. The anxiety in Boston was shown in a letter, under date of June 9, from his friend Hon. Edward L. Pierce, saying:-- “We have just heard of the threat of violence made to you last evening. Dr. Howe and others meditate leaving for Washington forthwith. I wish I could be there; but I feel assured that there are enough to protect you, if you will only let them. Do be careful, very careful. You will not be safe, until you have arrived in the Free States on your way home.” Messrs. Thayer and Eldridge, booksellers, wrote at once from Boston:-- “If you need assistance in defending yourself against the ruffians of the Slave Power, please telegraph us _at once_, or to some of your friends here who will notify us. There is a strong feeling here, and we can raise a small body of men, who will join with your Washington friends, or will alone defend you.” Hon. Gershom B. Weston, a veteran, wrote from Duxbury, Massachusetts:--