Celery Cream

1 head celery
1 pint water
1 pint milk or cream
1 table-spoon chopped onion
2 table-spoons white roux

Wash the celery. Cut it into small pieces. Throw it into one pint boiling salted water. Boil till very tender. Put through a sieve, and return to the water in which it was cooked. Boil the milk with the onion. Strain. Add the milk to the celery. Bring to the boil again. Stir in the white roux ([p. 12]). Season. Boil five minutes. Strain into soup tureen.