This section is from the book "Popular Law Library Vol7 Equity Jurisprudence, Trusts, Equity Pleading", by Albert H. Putney. Also available from Amazon: Popular Law-Dictionary.
Equity early took a different view of mortgage. Applying the doctrine that equity will look at the intent rather than the form, equity considered the debt as the principal thing and the mortgage merely as security therefor; with the result that a failure to pay the mortgage promptly on time was held not to work a forfeiture of the mortgagor's interest, but merely to render him liable for interest on the amount of the mortgage until its payment. In other words, the damage for the delay in the payment of the mortgage was considered the interest on the sum of money withheld for the time the same was withheld. At first equity only relieved against the forfeiture of the mortgagor's interest, when the act which worked such forfeiture was the result of an accident. Such relief, however, was soon extended to other cases.