2 lbs. of POTATOES, 1/2 stick of celery or the outer stalks of a head of celery, saving the heart for table use; 1 large Spanish onion, 1 pint of milk, 1 oz. of butter, a heaped up tablespoonful of finely chopped parsley, and pepper and salt to taste. Peel, wash, and cut in pieces the POTATOES, peel and chop roughly the onion, prepare and cut in small pieces the celery. Cook the vegetables in three pints of water until they are quite soft. Rub them through a sieve, return the fluid mixture to the Saucepan; add the milk, butter, and seasoning, and boil the SOUP up again; if too thick add more water. Mix the parsley in the SOUP just before serving.
The Allinson Vegetarian Cookery Book, by Thomas R. Allinson (Year 1915)