Thanks. I took your advice. Now sendmail initializes quickly and I can send messages without finding errors in the mail log. I receive messages that I send to my login id. I am concerned, however, about editing sendmail.cf, as you mentioned. And I wonder why I can't receive messages from my email address when I send them with the mail command. I don't see errors occur when I do this, but I don't receive the messages in my Mozilla inbox.
I also wonder about this message, which I see in my console.log:
Jul 9 17:17:44 localhost lookupd: DNSAgent: dns_send_query_server - timeout for 18.104.22.168