It shows that the doctor did not usually supervise the nurses closely.
Explanation:
In this passage, Nellie Bly develops the idea that the treatment of patients at Blackwell's Island was terrible. We know this because of the details provided in the text. We know that when the commissioner visited, the doctor made the rounds with him. They noticed that half the nurses were gone, which shows that he did not usually supervise the nurses closely. Because of this, it is likely that the patients did not receive the care they were meant to receive.
