31. When collecting accounts, a veterinary surgeon shall
(1) not sell or otherwise transfer his accounts of professional fees, except to another veterinary surgeon or to a partnership or joint-stock company within which the veterinary surgeon is authorized to carry on professional activities pursuant to a regulation made under the Professional Code (chapter C-26);
(2) ensure, where the veterinary surgeon practises within a partnership or joint-stock company, that the fees or prices relating to professional services provided by veterinary surgeons are always indicated separately on every invoice or statement of fees that the partnership or joint-stock company sends the client;
(3) ensure that the person appointed to collect the fees acts with tact and moderation; and
(4) collect interest on outstanding accounts only if there is a written agreement between the parties, provided that the interest thus required is reasonable.