In a heavy saucepan, saute bacon pieces until lightly browned. Add celery and onions and saute for 3 minutes without browning. Add remaining ingredients. Combine well and bring to a boil.
Simmer low about 2 1/2 hours, stirring occasionally. Remove meat from bone and discard bone. Cool the soup. Put through blender. Reheat and serve with lemon slices on top.