They breed leeches in special filtered water in reservoirs .

在蓄有特殊过滤水的贮水池中饲养水蛭。

Historically and even today leeches are used in medicine .

自古至今，蚂蟥都可作药用。

Its dna was found inside four of the leeches tested .

如今它的dna在受检测的4条水蛭中被发现。

The beeches and leeches alone could take weeks .

把山毛榉和水蛭分开得需要几个星期。

Now it successfully grows medical leeches in artificial conditions to produce cosmetics .

目前该中心成功地人工培植医用水蛭用于生产化妆品。