为什么会出现删除线?

我下载一个Xml文件，大约有六万条数据，我用php读取，echo出来，在第16710条时出现文本删除线，这是为什么?

$xml = simplexml_load_file('JACS.xml'); 
$num=0;
foreach($xml->PubmedArticle as $ArticleInfo) 
{ 
   $num++;
   echo $num;
   echo '<br><br>';
   $PubTime=$ArticleInfo->MedlineCitation->Article->Journal->JournalIssue->PubDate; 
   echo 'PublicationDate:'.$PubTime->Year.' '.$PubTime->Month.' '.$PubTime->Day.'<br><br>';
   $JournalName=$ArticleInfo->MedlineCitation->Article->Journal->Title;
   echo 'JournalName:'.$JournalName.'<br><br>';
   $PubTitle=$ArticleInfo->MedlineCitation->Article->ArticleTitle;
   echo 'Title:'.$PubTitle.'<br><br>';
   $PubAbstract=$ArticleInfo->MedlineCitation->Article->Abstract->AbstractText;
   echo 'Abstract:'.$PubAbstract.'<br><br>';
   echo 'Author:';
   $Authorlist=$ArticleInfo->MedlineCitation->Article->AuthorList;
   foreach($Authorlist->Author as $publisher)
   {
       echo $publisher->ForeName.' '.$publisher->LastName.'|';
   }
   echo '<br><br>';
   $Affiliation=$ArticleInfo->MedlineCitation->Article->AuthorList->Author[0]->AffiliationInfo->Affiliation;
   echo 'Affiliation:'.$Affiliation;
   echo '<br><br><br><br>';
}