This section is from the book "Philadelphia Cook Book: A Manual Of Home Economies", by Sarah Tyson Heston Rorer. Also available from Amazon: Philadelphia Cook Book.
Larding pork should be salt, solid, and clear fat without any streaks of lean. Cut into thin even slices, and cut these slices into long narrow strips, that will fit the larding-needle you intend to use. For Beef a la Mode the lardoons should be about the size of a lead-pencil. For veal, turkey, chicken, birds or sweetbreads, they should be about half that size. About one inch from the rind of the pork you will notice a decided mark or streak; below this and nearest the rind, is the muscular part of the pork, and the only part that can be used for larding. Above this the pork is so tender that it will break when you put it in the needle. After you cut these strips (lardoons they are now called), put them into a bowl of very cold water to harden. Place one lardoon into the slot end of the larding-needle as far as it will go, thrust the needle into the meat, taking a stitch about one inch deep, push the needle through, place the finger lightly on the strip of pork, and draw the needle out, leaving the pork exposed about a quarter-inch at each end of the stitch, and so continue until you have finished.