Signature by X — Signature by Mark
Many notaries go through their entire career without understanding the necessity and importance of the Signature by X / Signature by Mark procedure  (Notarizing an X). If you have ever done a hospital signing, or signing for elderly, you might be accutely aware of the limitations that a signer has in tasks we take for granted.  Many elderly signers with physical disabilities can not even sign their own name, or more their own arm with any coordination.  This necessitates signature by X procedures.
 
What is Signature by X?
Signature by X is where the signer being notarized signs an X instead of a regular signature.
(1) You need two subscribing witnesses who witness the signature by X.
(2) The signer signs an X in your journal and on the document.
(3) Witness one signs the person’s first name in the document and journal
(4) Witness two signs the persons middle and last names in the document and journal.
(5) Document the ID’s and signatures of the witnesses in the document and journal
(6) Keep in mind that this is a very unusual notary procedure and is tricky.
 
Be careful!
If you have ever done a hospital signing, the signer could be drugged, may not have current ID, or may have overly zealous relatives who move the patient’s arm to get them to sign their name. This is not acceptable. The signer must sign their own name.  Arms of others may be used as braces to limit the motion of the patient’s arm, but you may not actually move the signer’s arm around, otherwise that is like forgery — well intentioned forgery — which is still illegal.
 
Subscribing witnesses?
What is a subscribing witness?  Anyone who witnesses someone signing by X is a subscribing witness.  They sign the document and the journal.  In California, one witness signs the signer’s first name and the other signer signs the signer’s last and milddle name (if there is one ). Its good to create documentation to accompany the document as to what this odd procedure is, since it is uncommon and looks strange.  Its prudent to indicate the subscribing witnesses names on the actual document and that they witnessed the signature by X.
 
Comprehension
When notarizing the elderly, make sure they understand the document. The last thing you want is to end up in court because an elderly person has been defrauded out of their life savings with paperwork notarized by you.  Make sure the signer has read all the documents.  Elderly people get scammed much more than the rest of us simply because they are more vulnerable and less on the ball, especially when they are regularly drugged in a hospital.
 
Related Terms:
http://www.123notary.com/glossary/?subscribing-witness
http://www.123notary.com/glossary/?signature-by-mark

You might also like:

Where do credible witnesses sign the notary journal book?
http://blog.123notary.com/?p=2508

How much can a notary charge for swearing in a witness
http://blog.123notary.com/?p=2447

Notary Public 101 – a free notary course
http://blog.123notary.com/?p=19493

Notarizing the elderly – do more digging to be sure it is legit
http://blog.123notary.com/?p=20038