def getAbstract(trgd):
    """Traverse the document tree to get to the abstract
    """
    doctype = trgd.firstChild
    stylesheet = doctype.nextSibling
    annotation = stylesheet.nextSibling
    pubmedArticleSet = annotation.firstChild
    pubmedArticle = pubmedArticleSet.firstChild
    medlineCitation = pubmedArticle.firstChild
    PMID = medlineCitation.firstChild
    article = PMID.nextSibling
    articleTitle = article.firstChild
    abstract = articleTitle.nextSibling
    return abstract