This section of the book is from the "Canadian Banking Practice" book, by John T. P. Knight.
Question 21.— Which is correct of the following forms of signature by an attorney:
A.B. A.B. p. pro. A.B.
p. pro. C.D. p. pro. C.D. Att'y. C.D.
or is there a more correct form?
Answer.—The first form is erroneous; if it has any meaning it is that A.B. is signing on behalf of C.D.; the second is no better; the third form is quite correct and that commonly used in England. The abbreviation in "p. pro.'' or "per pro." (per procuratione) signifies that the signature is affixed by the agent of and under the authority of the party whose name follows, and may be read " by authority of A.B., C.D."
There is no better form than the last quoted in the enquiry, but " A.B. per C.D.," " A.B. by C.D.," " For A.B., C.D.," " A.B., by C.D., Att'y," are all in common use, and quite permissible; the chief point is that the form employed should clearly indicate that C.D. is acting as the agent of A.B. in the matter.