Nathan Clifford

“ Unquestionably the withdrawal of one ingredient in a patented combination and the substitution of another which was well known at the date of the patent as a proper substitute for the one withdrawn, is a mere formal alteration of the combination; and if the ingredient substituted per forms substantially the same function as the one withdrawn it would be correct to instruct the jury that such a substitution of one ingredient for another would not avoid the charge of infringement. ”

“ Mere formal alterations of a combination in letters-patent do not constitute any defence to the charge of infringement, as the inventor of a combination is as much entitled to suppress every other combination of the same ingredients to produce the same result, not substantially different from what he has invented and caused to be patented, as the inventor of any other patented improvement. ”

“ Patentable inventions may consist entirely in a new combination of old ingredients whereby a new and useful result is obtained, and in such cases the description of the invention is sufficient if the ingredients are named, the mode of operation given, and the new and useful result is pointed out, so that those skilled in the art, and the public may know the nature and extent of the claim and what the parts are which co-operate to produce the described new and useful result. ”