"It's getting too hard to try to make you money in this market," Jim Cramer told viewers of his "Mad Money" TV show Tuesday. "In this bear market, the only concern should be to protect the money you have." According to Cramer, one of the few remaining high-growth, defensive themes that's still working is pet diagnostics. Idexx Labs ( IDXX), Cramer says, is the best of breed, which offers an integrated play on pet diagnostics. Idexx makes a pet diagnostic test for veterinarians and offers a full range of services, including management software and laboratory services. "Even in a recession," Cramer said, "people still spend money on their pets."