If you've been in business for 100 or more years and are still going strong, you've done something right. And that's certainly fair to say about Fisher Scientific (NYSE:FSH) -- a very large lab and research supply company that has outlived former members of the Dow Jones index like U.S. Leather Company, Tennessee Coal, Iron, and cryptically named North American Company.

Investors will likely look at Fisher's fourth-quarter earnings report the way they would a good abstract painting: each will draw slightly different conclusions about what the picture really is. For instance, reported growth of nearly 8% is good, and currency-adjusted growth of 9% is even better, but organic growth of about 6% seems a little less exciting.

On the profitability side, adjusted operating income jumped 22% and net income climbed more than 29% on a pro forma basis. And for you cash flow folks, there was good news as well -- Fisher's free cash flow jumped more than 61% from last year's level, though some investors might want to adjust the capital spending number to factor in the company's ongoing acquisitions.

What still troubles me about Fisher, though, is the return on invested capital. Doing a quick and dirty back-of-the-envelope calculation, it looks like Fisher produced an ROIC of about 7.5% for 2005. That number just doesn't strike me as being as strong as it should be given the size and scope of this company. Now I'll grant that Millipore (NYSE:MIL) and Sigma-Aldrich (NASDAQ:SIAL) aren't entirely fair comparisons, but they serve many of the same markets and generate better returns.

Ultimately, that's a big hang-up for me, because I believe in the notion that ROIC is a good means of separating the wheat from the chaff in the investment world. I see plenty of opportunity for improvement at Fisher -- better margins from more private-label sales, overall margin leverage from a larger revenue base, future acquisition targets that would add to earnings, etc. But I just can't see why I should put my money with folks who aren't going to generate a superior return on it.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).