Dear Susan, I don't think that the anatomy book referred to in _Tom Sawyer_ can be Gray's, unless Twain was committing an anachronism. This year marks the 150th anniversary of its publication in Britain, but I don't believe it was published in the U.S. until twenty years later--1878 or even later. But there were a fairly large number of anatomy books available in the first half of the 19th C, I believe, including some that had been around and in use since the mid-18th C. K. Patrick Ober's excellent _Mark Twain and Medicine_ includes discussion of some of the books and practitioners who influenced Twain. Dr. Ober might actually know offhand which anatomy is most likely to be the one referred to in _TS_. I don't know whether he is still on the list, but you might email him. Huck mentions several books that are not "textbooks," per se, but were common in people's homes, such as _Gunn's Domestic Medicine_, but that may go far afield from what you're looking for. A fascinating topic. Best, Sharon McCoy