Pour water over clams, then drain. To water add hard
part of clams finely chopped. Heat slowly to boiling-point,
cook twenty minutes, then strain. Cook butter with onion
five minutes; remove onion, add flour and gradually clam
133water. Add cream, soft part of clams, and as soon as
boiling-point is reached, tomatoes to which soda has been
added. Season with salt and cayenne, and serve at once.