Can't find the_content in index.php

I’m trying to use actual excerpts on my main page (not <!–more–>), but all the documentation I can find says to replace <?php the_content; ?> with <?php the_excerpt; ?>. The only problem is that I can’t find that line in my index.php. Instead, here’s my loop:

<?php /* Start the Loop */ ?>
<?php while ( have_posts() ) : the_post(); ?>
<?php get_template_part( ‘content’, get_post_format() ); ?>
<?php endwhile; ?>

What am I missing? site: http://www.meandmydiy.com
Thanks