Final answer:
Based on the given information, we cannot determine the specific month in which the number of men leaving the war exceeded the number of men joining the war.
Step-by-step explanation:
In the question, it is asked in which month did the number of men leaving the war exceed the number of men joining the war. Unfortunately, the chart showing the enlistment/casualty rate is not provided, so we cannot examine it. However, based on the information given, we can understand that both sides of the Civil War, the North and the South, faced difficulties in recruiting enough men as the war continued.
This indicates that there may have been a point when the number of men leaving the war exceeded the number of men joining it. To determine the exact month, we would need additional information. Therefore, we cannot definitively answer this question based on the given information.