who came up with the doctrine of signatures
Doctrine of signatures Paracelsus (1493–1541) developed the concept, writing that "Nature marks each growth ... according to its curative benefit",[1] and it was followed by Giambattista della Porta in his Phytognomonica (1588).
Medallion signature guarantee A medallion signature guarantee is a binding warranty, issued by an agent of the authorized guarantor institution, that: (a) the signature was genuine; (b) the signer was an appropriate person to endorse, and (c) the signer had legal capacity to sign. A medallion signature guarantee is not equivalent to an American Notarial act. One American Notarial act, called an acknowledgment, is a formal declaration made before an authorized public officer (i.e., notary public, judge, or justice). It is made by a person executing an instrument who states it was his "free act and deed". The three essential components of an acknowledgment are: (a) the personal appearance before an authorized public officer; (b) positive identification; (c) the actual acknowledgment of signing. Unlike medallion signature guarantees, the person executing many legal documents does not have to sign his name in the physical presence of the issuing officer (i.e., notary public, judge, or justice).