Wash, scrape, and cut the carrots into dice. Prepare and cut up the onions and celery.
Set the vegetables over the fire with 3 pints of water, adding the mace and seasoning.
Let all cook until quite soft, which will probably be in 1 1/2 hours.
If the carrots are old, they will take longer cooking.
When the vegetables are tender, rub all through a sieve, return the soup to the saucepan, add the butter, allow it to boil up, and serve with sippets of toast.