I think I can guess.

You did not show me your boy's letter of this morning." "There it is!" And the poor mother, with her tears fast flowing--they had been restrained so long that now they burst out like a tide--gave way to that heart-break which many a mother has had to endure--the discovery that her son was not the perfect being she had thought him; that he was no better than other women's sons, and equally liable to fall away.
Poor Cardross had been doing all sorts of wrong and foolish things, which he had kept to himself as long as he could, as long as he dared, and then had come, in an agony of penitence, and poured out the whole story of his errors and his miseries into his mother's bosom.
They were, happily, only errors, not sins--extravagancies in dress; amusements and dissipations, resulting in serious expenses; but the young fellow had done nothing absolutely wicked.

In the strongest manner, and with the most convincing evidence to back it, he protested this and promised to amend his ways, to "turn over a new leaf," if only his mother would forgive him, and find means to pay the heap of bills which he enclosed, and which amounted to much more than would be covered by his yearly allowance from the earl.
"Poor lad!" said Lord Cairnforth, as he read the letter twice over, and then carefully examined the list of debts it enclosed.

"A common story." "I know that," cried Helen, passionately.

"But oh! That it should have happened to my son!" And she bowed her face upon her hands, and swayed herself to and fro in the bitterest grief and humiliation.
The earl regarded her a little while, and then said, gently, "My friend, are you not making for yourself a heavy burden out of a very light matter ?" "A light matter?
But you do not see--you can not understand." "I think I can." "It is not so much the thing itself--the fact of my son's being so mean, so dishonest as to run into debt, when he knows I hate it--that I have cause to hate it, and to shrink from it as I would from--But this is idle talking.