They seem to have forgotten that one.
I hope you make a mint on the shirts, Gregory.
UPDATE: Generally the quote is "Primum Non Nocere," but Gregory replies in an email:
Although “non” is considered proper, both are actually acceptable. My use of the “nil” variant was due to the essay linked below by Dr. Milton R Wolf, a cousin of Barack Obama, who utilized the “nil” variant while addressing the health care reform bill.And he adds a new version of the Caduceus as requested by my readers:
There is madness to my method :)
Batwings and fangs, oh my!