Allan Pinkerton, The spy in the rebellion; being a true history of the spy system of the United States Army during the late rebellion, revealing many secrets of the war hitherto not made public, compiled from official reports prepared for President Lincoln , General McClellan and the Provost-Marshal-General .

At this time the position of Maryland was rather a precarious one. There could be no doubt that the Unionists were greatly in the majority, but it was also true that there was a large and influential minority of her people in favor of secession. Here, as elsewhere, conspiracy had been at work for months, and many of the prominent political leaders were in full accord with the rebel government. The legislature was believed to be unreliable, and treason had obtained so firm a foothold in the populous city of Baltimore, that a secret recruiting office was sending enlisted men to Charleston. The venomous germ of treason, once planted, grew in magnitude and virulence, until it finally culminated in the infamous riot of April g9th, when the blood of the citizen soldiery of Massachusetts was first shed in defense of the Union. A spirit of opposition to the passage of Northern troops through the city, on their way to the seat of government, had been engendered among the “rough” element of Baltimore, and the excitement reached its climax upon the arrival of the Sixth Massachusetts Regiment, which was the first to answer the call for troops. When their presence became known the traitorous element could no longer be restrained, and while the men were passing quietly