Stocks Rise as Merck Shares Help Lift Dow  NEW YORK (Reuters) - U.S. stocks traded higher on  Wednesday, with shares of drugmaker Merck   Co. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=MRK.N target=/stocks/quickinfo/fullquote"&gt;MRK.N&lt;/A&gt; helping  to boost the Dow after its 2005 forecast offered relief to some  investors on Wall Street.