PHILADELPHIA — Mütter Museum curator Anna N. Dhody opened a package Tuesday morning that arrived at the museum by mail. Inside was a glass jar containing two preserved fetuses, and a letter from someone claiming to be a retired physician who wanted to make a donation. “I saw the letter and was like, ‘Oh no, no no, I have to make a few calls,’” said Dhody, who promptly called the police. “This is not normal procedure.” The package was addressed to Dhody, but did not have a return address. The letter was scant and included no other details about the sender or the fetuses, Dhody said. Police are …