Science News SCIENCE NEWS + See all authors and affiliations Science 20 Nov 1931:Vol. 74, Issue 1925, pp. 10-14DOI: 10.1126/science.74.1925.10 Article Info & Metrics eLetters PDF This is a PDF-only article. The first page of the PDF of this article appears below.
Science Vol 74, Issue 192520 November 1931 Table of Contents Print Table of Contents Front Matter (PDF)
