Each business day, TheStreet.com Ratings compiles a list of the top five stocks in five categories -- fast-growth, all-around value, large-cap, mid-cap and small-cap -- based on data from the close of the previous trading session.Today we focus on mid-caps. These are stocks of companies that have market capitalizations of $500 million to $10 billion that rank near the top of all stocks rated by our proprietary quantitative model, which looks at more than 60 factors. In addition, the stocks must also be followed by at least one financial analyst who posts estimates on the Institutional Brokers' Estimate System. They are ordered by their potential to appreciate. Note that no provision is made for off-balance-sheet assets such as unrealized appreciation/depreciation of investments, market value of real estate or contingent liabilities that might affect book value. This could be material for some companies with large underfunded pension plans. Perrigo ( PRGO) is a global health care supplier that manufactures over-the-counter pharmaceutical and nutritional products for the store-brand market. We have rated Perrigo a buy since March 2007 due to a variety of strengths. For the fourth quarter of fiscal 2008, the company reported that its revenue rose 32.3% year over year. This growth appears to have trickled down to the company's bottom line, boosting EPS from 20 cents in the fourth quarter of fiscal 2007 to 30 cents in the most recent quarter. Net income also increased, rising 46.5% when compared with the same quarter last year. In addition, Perrigo increased its net operating cash flow by 106.00% year over year.