Public Domain Mark
You can use this work for any purpose without restriction under copyright law. Read more about this licence.
Credit
Die wissenschaftliche Ueberzeugung, ihre Stufen und Schranken : mit besonderer Bezugnahme auf H. Helmholtz / von W. Oehlmann. Public Domain Mark. Source: Wellcome Collection.
Provider
This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.