Try this in display.js.erb:
$('#notify').append('<%= escape_javascript(render :partial => 'layouts/activity', :collection => @activities) %>');
Then, try this in _activity.html.erb:
<%= ActivityPresenter.new(activity, self).render_activity %>
To ensure that whenever the user clicks on "Display' the display
action is invoked, you will need to adjust your routes.rb file, which is located in the config directory. You could do something like this in routes.rb:
get '/activities/display', 'activities#display', as: :activity_display
Once you make that change in routes.rb, you can edit your link_to
like this:
<%= link_to "Display", activity_display_path, :remote => true %>