Surrounded By Rats - She Likes It -- Joey takes his "medicine" - vitamin D. Girl in a thousand is 18 years old Daphne Hislop, who works in the Crookes Laboratories, Park Royal, Loudon - for she makes pets of her rat family used for vitamin research and Daphne has more than 1,000 rats to care for, Joey, the one in these pictures, is a special favourite. He was once a poor specimen suffering from rickets, but vitamin D oil in his food has made him a sleek, fine fellow. February 26, 1947. (Photo by Mirror Features).