It was a "speciality camp" of Medical Corps members including vetrinary. There are several mentions in GA History resources. Also have you seen this website?
http://freepages.genealogy.rootsweb.ancestry.com/~gregkrenze...Georgia Archives has a growing digital records being put online.
Look for books put digitally online at Google Books and Archive.org or just search E-Books.
Also here is a great WWI site in my opinion. He may have had basic training in his home or enlistment state then sent to Camp Greenleaf.
http://freepages.military.rootsweb.ancestry.com/~worldwarone...