I don't remember the two-headed dog at all.
I watched this movie the night before I had to fly back here from R&R leave and all I really remember was being kind of confused.
But the removing the head thing is very similar to a sub-plot in the novel The Tomorrow File, however in the book the head was kept alive without being reattached to another body. The scientist in the novel even did the experiment on a dog first, before performing the surgery on a human. I wonder if they got the idea for the movie from this book. Hmmm....
Major K
"He guards the sleep of his pauper master as if he were a Prince." George Graham Vest
"We are alone, absolutely alone on this chance planet: and, amid all the forms of life that surround us, not one, excepting the dog, has made an alliance with us." - Maurice Maeterlinck