58 ESSENTIALS OF VETERINARY LAW 
such rights and privileges as its wording shows. 
A license to practice veterinary medicine would 
give no right to prescribe for a human being. 
Whenever the existence of a license is lawfully 
questioned, it is not sufficient to prove its posses- 
sion by parol evidence, nor is it sufficient to pro- 
duce a certificate that one is licensed.** The license 
may be a forgery, or it may have been canceled, or 
the certificate may be wholly false. By the gen- 
eral rules of evidence, when the existence of a 
document is asserted, the document itself should 
be produced.*® The same statements are true as 
to the possession of a diploma. The diploma itself 
should be produced. It may be possible that the 
lawfully issued diploma might have been de- 
stroyed, and that a duplicate diploma could not 
possibly be procured. It would, under such condi- 
tions, be an injustice to the victim of misfortune 
to enforce this rule; but the greatest caution is 
needed in accepting proofs in such a case. This 
was illustrated in a case which came under the 
writer’s personal observation. A physician 
claimed to have been graduated from an institu- 
tion which ceased to exist during the Civil War. 
He claimed that many years afterward his office 
was burned and that his diploma was destroyed. 
He made affidavit of these facts, or asserted facts. 
Owing to the writer’s official relation with a medi- 
cal society the applicant was referred to him for 
recognition. In spite of recommendations from 
physicians and clergymen, a cross examination, 
34 Commonwealth v. Spring, 35 Greenleaf, Evidence, 79; 
19 Pick. 396. Wharton, Criminal Law, 2434. 
