Wipe out the soup pot and place over moderate heat. Add the bacon and cook, stirring occasionally, until crisp, about 12 minutes. Add the onions, carrots, celery, 2 teaspoons of salt, cayenne and the bay leaf. Cook until the vegetables are soft, about 10 minutes. Stir in the flour and cook until it begins to stick to the bottom of the pan, about 2 minutes. Stir in the clam-broth mixture and bring to a boil. Add the potatoes, corn and Old Bay and simmer over moderately low heat until the potatoes are tender, about 15 minutes. Stir in the half-and-half, parsley, Worcestershire sauce and Tabasco. Remove from the heat and stir in the clams. Discard the bay leaf and season the chowder with salt and pepper. Ladle the chowder into bowls and serve.