Wash celery; cut into 1/2 inch slices (5 cups), reserving tops.
Combine celery, tops, boiling water, and 1/2 tea-Spoon salt.
Cook till celery is tender, 12 to 15 minutes.
Discard tops; drain, reserving 1/2 cup cooking liquid.
Melt the 3 tablespoons butter.
Blend in flour, 1/2 teaspoon salt, and 1/4 teaspoon pepper.
Add milk and reserved liquid.
Cook and stir till thickened.
Remove from heat.
Stir in celery and half the nuts.
Turn into 1-quart casserole.
Top with remaining nuts.
Combine melted butter and crumbs; sprinkle atop.
Bake at 350° till heated through, 20 to 25 minutes.