made available to the public (whether in the Republic or elsewhere) by written or oral description, by use or in any other way. (7) The state of the art shall also comprise matter contained in an application, open to public inspection, for a patent, notwithstanding that that application was lodged at the patent office and became open to public inspection on or after the priority date of the relevant invention, if— (a) that matter was contained in that application both as lodged and as open to public inspection; and (b) the priority date of that matter is earlier than that of the invention. [Sub-s. (7) substituted by s. 31 (b) of Act No. 38 of 1997.] (8) An invention used secretly and on a commercial scale within the Republic shall also be deemed to form part of the state of the art for the purposes of subsection (5). (9) In the case of an invention consisting of a substance or composition for use in a method of treatment of the human or animal body by surgery or therapy or of diagnosis practised on the human or animal body, the fact that the substance or composition forms part of the state of the art immediately before the priority date of the invention shall not prevent a patent being granted for the invention if the use of the substance or composition in any such method does not form part of the state of the art at that date. [Sub-s. (9) substituted by s. 31 (c) of Act No. 38 of 1997.] (10) Subject to the provisions of section 39 (6), an invention shall be deemed to involve an inventive step if it is not obvious to a person skilled in the art, having regard to any matter which forms, immediately before the priority date of the invention, part of the state of the art by virtue only of subsection (6) (and disregarding subsections (7) and (8)). [Sub-s. (10) substituted by s. 31 (d) of Act No. 38 of 1997.] 26. (11) An invention of a method of treatment of the human or animal body by surgery or therapy or of diagnosis practised on the human or animal body shall be deemed not to be capable of being used or applied in trade or industry or agriculture. (12) Subsection (11) shall not prevent a product consisting of a substance or composition being deemed to be capable of being used or applied in trade or industry or agriculture merely because it is invented for use in any such method. Prior knowledge or publication of invention excused in certain circumstances. A patent shall not be invalid by reason only of the fact that the invention in respect of which the patent was granted or any part thereof was disclosed, used or known prior to the priority date of the invention— (a) if the patentee or his or her predecessor in title proves that such knowledge was acquired or such disclosure or use was made without