Read these lines from the excerpt again: He was restive all through it, he kept tally of the details of the prayer, unconsciously—for he was not listening, but he knew the ground of old, and the clergyman's regular route over it—and when a little trifle of new matter was interlarded, his ear detected it and his whole nature resented it he considered additions unfair, and scoundrelly

Which word from the excerpt helps define the word interlarded?