Depending on how your fishmonger supplies the herring, you may have to remove the bones yourself - cut along the underside of the herring, lay it on a table, cut side down and hit across the backbone in a few places with a rolling pin or your hand. Remove the backbone and as many of the smaller bones as possible. Scrape the scales from the fish with a knife, remove heads and tails.
Sprinkle with salt and pepper and either toss them in a plastic bag with plenty of oatmeal or put the fish on a plate and coat them with oatmeal - you may have to press the oatmeal into the fish to ensure it is fully covered. Fry in meat dripping or cooking oil - put them in with the skin side upwards first. Fry until lightly brown, turn and cook the other side. It should take 5/7 minutes. Drain the fish on kitchen paper (paper towels).
Modern books suggest serving with lemon and parsley - old Scots would not have known such refinements!