Meetings & Meeting Reports Forthcoming Events See allHide authors and affiliations Science 15 Dec 1961:Vol. 134, Issue 3494, pp. 1990-1994DOI: 10.1126/science.134.3494.1990 Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears below.
Science Vol 134, Issue 349415 December 1961 Table of Contents Print Table of Contents Ed Board (PDF) Front Matter (PDF)
