The dangers of the world is another theme in the book. Once the reader has completed the entire work, it becomes clear that there are an abundance of dangerous bacteria, viruses, metals and chemical agents which have the ability to cause serious illness and death. While most individuals have certainly heard about hepatitis, botulism, streptococcus, staphylococcus, and other bacterial and viral infections which cause a wide variety of ailments, most do not think of many others covered in this book.