What is one central idea of Nurse and Spy in the Union Army?

COMMENCEMENT OF THE WAR—MY HOME AND MY DUTY—I ENLIST IN THE CAUSE—EXCITEMENT AT THE WEST—TROOPS ON THE MARCH—MOBS AT BALTIMORE—TEMPORARY HOSPITALS—UNAVOIDABLE EVILS—BEGGING FOR COMFORTS—SUPPLIES FOR THE SICK—CAMP HOSPITALS—THUNDERS STORMS IN CAMP—A DYING OFFICER—SOLDIERS IN THE PUBLIC BUILDINGS—PREPARATIONS FOR THE ADVANCE.

Explanation:

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