Likely a sterile medium means an uncontaminated culture (food free of living organisms) that will grow only the new bacteria introduced for analysis. Source(s): http://www.thefreedictionary.com/sterile
Stonepelt was Bluestar's first mentor and a very well-respected senior warrior of ThunderClan. It is revealed in this book that he took her to the Gathering on her second day as an apprentice because she had caught a squirrel very well for a new apprentice, and the squirrel had been as big as she was.
2 Bluestar Bluestar is a character in the Warrior Cats series. She one of the leaders of ThunderClan. She is mates with Oakheart of RiverClan and her kits, Stonefur and Mistyfoot, live in RiverClan. Bluestar can be negative at times, but she is wonderful.