I ended up putting my companion of 12 years down tonight. As mentioned previously in this thread, she had a malignant tumor on her paw.. and last weekend she ripped the tumor open and it's been bleeding on and off ever since. She could barely walk at all and when she did, she tried hopping everywhere. The vet said it wasn't going to get any better and it was likely quite painful for her. It's extremely hard when the animal is mentally alert and still seemed spry for her age, save for having the tumor on her paw. The vet said that if the tumor was elsewhere, she'd recommend waiting until the cancer took more of a toll on her health, but given that it was on the bottom of her foot, it was torture to keep going.... malignant tumors don't heal.