561. Admissibility of evidence.

Whether validity is attacked or not, evidence of the state of common general knowledge, and of the meaning of technical terms, is always admissible for the purpose of enabling the court to construe the specification1, but for this purpose the evidence must be strictly confined to what the skilled addressee2 might be presumed to have known at the date of filing3, and does not authorise a reference to patent specifications or little known scientific journals4, unless they form part of the addressees common general knowledge5.

Oral evidence given for the claimant in a former action cannot be used against him