Can anyone explain why this code fails?

Trying to apply wordpress function results to my php variables for display.

I get the results from the functions the_date(), the_title(), etc. but the text does not display correctly in the DIVs. What is going on here? Why does this NOT work?

$home_content .= "<div style=''>";
$posts = get_posts('numberposts=10&order=ASC&orderby=post_title');
foreach ($posts as $post) : setup_postdata($post);
$home_content .= "<div style='color:red;font-size:12px;'>".the_date()."</div>";
$home_content .= the_title();
$home_content .= the_excerpt();
endforeach;
$home_content .= "</div>";