PATENT LAW
Gillette defence of applying the prior art
• secure if he knows that that which he is doing differs from that which has been done of old only in non-patentable variations, such as the substitution of mechanical equivalents or changes of material, shape, or size. The defence that 'the alleged in-fringement was not novel at the date of the plaintiff's letters patent,' is a good defence in law, and it would sometimes obviate the great length and expense of patent cases if the defendant could and would put forth his case in this form, and thus spare himself the trouble of demonstrating on which horn of the well-known dilemma the plaintiff had impaled himself, invalidity or noninfringement
IPPT1913, UKHL, Gillette Safety Razor v Anglo-American Trading
