Merck has entered an agreement to acquire Schering-Plough in a stock and cash transaction valued at $41.1 billion. The merger will combine the two companies under the name Merck. Schering-Plough shareholders will receive 0.5767 shares and $10.50 in cash for each share they hold. Each Merck share will automatically become a share of the combined company. Merck chairman, president and chief executive officer Richard T. Clark will lead the combined company. Upon closing, Merck shareholders are expe...