Question: What is the actor's middle name that voices the character Dr. William MacDougal?

Context paragraphs:
Groundskeeper Willie: Dr. William MacDougal, usually known as Groundskeeper Willie, is a recurring character on "The Simpsons", voiced by Dan Castellaneta.  He is the head groundskeeper at Springfield Elementary School.  Willie is almost feral in nature and is immensely proud of his native Scotland.  He is easily identifiable by his flaming red hair and beard, as well as his aggressive temperament and thick though inaccurate Scottish accent.

Dan Castellaneta: Daniel Louis Castellaneta ( ; born October 29, 1957) is an American actor, voice actor, comedian and screenwriter.  Noted for his long-running role as Homer Simpson on the animated television series "The Simpsons", he also voices many other characters for the show, including Abraham "Grampa" Simpson, Barney Gumble, Krusty the Clown, Sideshow Mel, Groundskeeper Willie, Mayor Quimby and Hans Moleman.

Cascade Mansion: The Cascade Mansion is the name of an antebellum home built in south west Atlanta, Georgia, south of the Sandtown (Now Cascade Road) built by Dr. William Poole and Elizabeth Gilbert Poole, son in law of the first physician Dr. William Gilbert in Fulton County, Georgia.  The home was begun in construction in 1860 and was incorrectly identified by soldiers of the US XXIII Army Corps during the siege of Atlanta as the "Head House."  The home served briefly as the Headquarters of Confederate Major General William B. Bate, attached to S.D Lee's Corps during the Battle of Utoy Creek, August 1–7, 1864.  The home and grounds served as a US Army Hospital during the Siege of Atlanta for the XXIII and later XIV Corps in August 1864.  The home is of the antebellum style on the former East Point Road (now Dodson Drive SW) in Atlanta.  The interior was finished in the Victorian style in 1869–70.

Dr. William Snowden House: The Dr. William Snowden House was used as a hospital operated by its owner, Dr. William Snowden, and Dr. Snowden's wife, Amarynthia Yates Snowden.  When bombardment of the city forced the Snowdens to evacuate to Columbia, South Carolina, the family's silver was buried in the yard; it was not unearthed until the 1920s when a box of the silver was found during landscaping work.  After the Civil War, meetings were held in the house that led to the formation of the Confederate Home and College.  The house was itself mortgaged to fund the creation of the institution, which existed to care for wives and daughters of Confederate soldiers.

Dr. William J. Mayo House: The Dr. William J. Mayo House was built in 1916.  The house showcases a unique combination of Renaissance Revival and English Tudor styles.  The 24,000 square foot home contains 47 rooms on 6 floors.  Also known as the Mayo Foundation House, it was listed on the U.S. National Register of Historic Places in 1975.  It was a home of Dr. William James Mayo (1861–1939), one of seven founders of the Mayo Clinic.  It was donated by Dr. Mayo in 1938 to serve as a meetingplace for the Mayo Foundation, and today is commonly called the Foundation House.

Frederick Twort: The eldest of the eleven children of Dr. William Henry Twort, Frederick Twort was born in Camberley, Surrey on 22 October 1877.  The three eldest sons went to Tomlinson's Modern School in Woking.  From 1894 Frederick studied medicine at St Thomas's Hospital, London.  After qualifying in medicine (Membership of the Royal College of Surgeons, Licentiate of the Royal College of Physicians) in 1900, Twort took the first paid post available, assistant to Dr. Louis Jenner, Superintendent of the Clinical Laboratory of St Thomas' Hospital.  There he trained in pathological techniques.  In 1902 he became assistant to the Bacteriologist of the London Hospital, Dr. William Bulloch, later F.R.S., and carried out single-handed the whole diagnostic routine of the Hospital.  In 1909, Twort became the superintendent of the Brown Animal Sanatory Institution, a pathology research centre, and remained there for the duration of his career.  In 1919 Twort married Dorothy Nony, daughter of Frederick J. Banister, and together they had three daughters and a son.

Elim (Bethel, Missouri): Elim, also known as the Dr. William Keil House, is a historic home located near Bethel, Shelby County, Missouri.  It was built in the late-1840s, and is a 2 1/2-story, brick and stone dwelling over a full basement.  It has a simple ridge roof and two porches.  It was built by the members of the "Society of Bethel" and served as the residence of the society's founder Dr. William Keil (1812-1877).

Dr. William B. Pritchard House: Dr. William B. Pritchard House is a historic home located at Princess Anne, Somerset County, Maryland.  It is a 2 ⁄ -story, five-bay, frame dwelling constructed in several stages between about 1860 and 1906.  It features a porch with a distinctive octagonal gazebo.  A traditional 19th-century farmhouse, it was reworked extensively around 1904–1906 in the Colonial Revival style by New York physician, Dr. William B. Pritchard as a country retreat.

Dr. William and Elizabeth Blackburn House: The Dr. William and Elizabeth Blackburn House is an historic two-story wooden house located at 219 South Tyler Avenue in Pierre, South Dakota.  Designed in the Stick or Eastlake style of Queen Anne style architecture, it was built in 1883 by local banker and real estate speculator, H. O. Fishback.  In 1887, it was bought by the Rev. Dr. William Maxwell Blackburn and his wife, Elizabeth Powell Blackburn, who had come to Pierre from Grand Forks, North Dakota, where he had been president of the University of North Dakota.  Dr. Blackburn, a Presbyterian minister, scholar and author became the founding president of the Presbyterian University of Southern Dakota, which later became Pierre University and served as such until his death in 1898.  Following his death, Pierre University was relocated to Huron, where it became Huron University.  Later owners include C. B. Billinghurst, local newspaper publisher, and Harold King and his wife Irma E. King.  The Kings ran a grocery store and he was a local politician while she was a poet.

Dr. William Columbus Cauthen House: Dr. William Columbus Cauthen House, also known as Oak View Farm, is a historic home located near Kershaw, Lancaster County, South Carolina.  It was built about 1848, and is a two-story, frame, weatherboarded, central-hall farmhouse, or I-house.  Also on the property are a log barn and a frame barn and shed.  It is the oldest known residence in Lancaster County and was the home of Dr. William Columbus Cauthen, who was involved in state politics.

Supporting paragraphs: Groundskeeper Willie Dan Castellaneta
Answer: Louis