Legal Dictionary of Pakistan

Markusk doctrine

Patents. An exception to the policy against use of alternative language in claims, by which in certain claims (esp. those involving chemical components) a claimant can use an alternative, subgeneric phrase when there is no applicable, commonly accepted generic expression. Ex parte Markush, 1925 Dec. Comm'r Pat. 126. "The Patent Office early adopted a policy against use of alternative language in claims. Thus, a claimant could not use the specific alternative phrase 'glass or plastic' but could use a generic phrase (such as 'impervious transparent material') that would cover effectively the desired alternatives. The Markush doctrine developed as an exception . . . . With chemical compounds there may be no suitable phrase to cover the alternatives. Under limited circumstances a claimant could use an artificial or coined subgeneric group in the form of 'material selected from the group consisting of X, Y, and Z.' " 2 Donald S. Chisum, Patents § 8.06[2], at 8-119 to 8-120 (1992).