I do not know the exact size of Camp Douglas, but believed it comprises from 60 to 70 acres of land. The prisoners square proper, covers about 20 acres. In November last it was enclosed by a board fence 12 feet in height and made of lumber an inch and a quarter in thickness. The boards were placed endways and were nailed from the inside. The outside sentinels were stationed on a parapet about three feet from the top of the fence on the outside. The camp was more easily assailable from without and less defensible than if the attack was made from inside. The Judge Advocate here exhibited to the witness a plan of the camp found on the person of one of the conspirators. _Colonel Sweet_.--The map is very roughly drawn and is a little out of proportion in detail, but is a correct drawing of the camp as it was in August and September of last year. The outlines are precisely the same. As shown on the map there were then 40 barracks in the prison square. This number is now increased. The Guard-house and small tents on the west side of the camp are also moved now. The barracks marked "Yankee Barracks" is the correct position of the barracks occupied by the garrison in Garrison Square. The building marked "Douglas House" on the South side of the camp is, I suppose the Douglas University. It is a magnificent building and is located about eighteen or twenty rods from the camp fence, and overlooks the entire camp. One hundred men, or even fifty men, stationed in that building, would command Camp Douglas, and almost make it untenable to any force. During the session of the Democratic Convention, and until the danger was over, I stationed two companies near that building. I had in my charge a prisoner named John T. Shanks at that time; he was there when I assumed the command of the camp, on the second of May, 1864. He was a clerk in the office for the commissary of prisoners. He applied to me to take the oath of allegiance during the summer. His application went through me to the Commissary General of Prisoners with my approval. I never approved these applications unless I was fully convinced that the applicant was desirous of becoming a loyal citizen. The application was not granted, but I made it the basis of communication to Commissary General that Shanks desired to serve the United States, and to take the oath. In this camp there were some men who were more largely entrusted than others. Shanks was a paroled prisoner, having the freedom of Garrison Square during the day time. There were others there in the same condition--a man named Grey, and clerks in the medical department. Shanks was allowed to go to the city two or three times in company with an officer. The prisoners are never permitted to have any funds. I gave Shanks a dollar.