Casaubon's library attack is a sudden collapse that exposes the danger beneath his apparent recovery and sharply changes Dorothea’s response to him: anger gives way to alarm, then to a demand for plain knowledge of his condition. The episode also makes clear that his scholarly work may itself have to be moderated to protect his health.

The Collapse in the Library

Before the attack, Dorothea had left Will Ladislaw’s letters unread on her husband’s writing-table. She had felt insulted by Casaubon’s displeasure over them, but did not understand its subtler causes; she turned instead to copying Latin quotations, taking satisfaction in the steadiness of her hand and her growing grasp of the construction.

The apparent quiet lasted about half an hour. Then a book struck the floor with a loud bang, and Dorothea saw Casaubon on the library steps, clinging forward in evident physical distress. She hurried to him, climbed onto a stool to reach his elbow, and asked, “Can you lean on me, dear?” Her anger had been displaced by tender alarm before either of them could settle the conflict that preceded the episode.

Casaubon remained unable to speak or move for two or three minutes, gasping for breath. He eventually descended the three steps and fell backward into the large chair Dorothea had drawn near the foot of the ladder. Though he had stopped gasping, he seemed helpless and close to fainting. Dorothea rang violently for assistance; he was moved to the couch and gradually revived without losing consciousness. Sir James Chettam arrived after hearing that Casaubon had suffered a fit in the library, and Dorothea herself proposed sending for a medical man.

Medical Warning and Uncertainty

Lydgate later described Casaubon as already nearly in his usual state of health and making faster progress than he had first expected. Dorothea nevertheless detected significance in his tone and asked whether the illness might return. Lydgate said that such cases were difficult to assess and that Casaubon would need close watching, particularly to avoid straining his nervous power.

Dorothea pressed him to speak plainly. She could not bear the possibility that there was something important she did not know and that knowledge of it might have changed how she acted. She set aside the formalities of bonnet and gloves, treating the question as one of destiny rather than polite consultation. Her response registers not only fear of the attack recurring but anxiety over whether she had failed to understand a fact that mattered to her conduct as a wife.

Lydgate identified mental agitation and excessive application as dangers. Dorothea immediately recognized what such advice might cost Casaubon: giving up his work would make him miserable. Lydgate proposed trying, by direct and indirect means, to moderate and vary his occupations. He believed the heart affection that had caused the attack posed no immediate danger if circumstances concurred happily, but warned that the disease might develop more rapidly and that death could sometimes be sudden. The attack therefore leaves his prognosis uncertain rather than resolving it into either safety or imminent death.

Consequences and Significance

The episode places Casaubon’s attachment to work in direct tension with the medical need to limit mental strain. Dorothea understands that the prescribed caution threatens a central source of his purpose, even as the possibility of sudden death makes inaction frightening. Her question, “Tell me what I can do,” turns concern into a request for practical responsibility, while Lydgate can offer vigilance and moderation rather than certainty.

The scene also marks a change in Dorothea’s immediate relation to Casaubon. She had been hurt and indignant over his conduct, but when his body fails she moves at once toward him, physically supporting him and summoning help. That care does not erase the earlier misunderstanding; instead, the attack forces her to confront the consequences of what she may not know. Its decisive effect is to make his vulnerability—and the possible cost of his continued scholarly application—impossible to treat as a merely private irritation.