I can think of no other excuse for her.

She would not accept it as an excuse for herself now. What she saw
with scorn was that she was always suspecting the worst of Tommy.
Very probably there was not a thought in the book that had been put
in with his old complacent waggle of the head. "Oh, am I not a
wonder!" he used to cry, when he did anything big; but that was no
reason why she should suspect him of being conceited still. Very
probably he really and truly felt what he wrote--felt it not only at
the time, but also next morning. In his boyhood Mr. Cathro had
christened him Sentimental Tommy; but he was a man now, and surely the
sentimentalities in which he had dressed himself were flung aside for
ever, like old suits of clothes. So Grizel decided eagerly, and she
was on the point of telling him how proud she was of his book, when
Tommy, who had thus far behaved so well, of a sudden went to pieces.

He and Grizel were together. Elspeth was a little in front of them,
walking with a gentleman who still wondered what they meant by saying
that they had heard his baby cry. "For he's no here," Corp had said
earnestly to them all; "though I'm awid for the time to come when I'll
be able to bring him to the Den and let him see the Jacobites' Lair."

There was nothing startling in this remark, so far as Grizel could
discover; but she saw that it had an immediate and incomprehensible
effect on Tommy. First, he blundered in his talk as if he was thinking
deeply of something else; then his face shone as it had been wont to
light up in his boyhood when he was suddenly enraptured with himself;
and lastly, down his cheek and into his beard there stole a tear of
agony. Obviously, Tommy was in deep woe for somebody or something.