Licence: Public Domain Mark
Credit: Gustav Robert Kirchhoff. Wood engraving. Wellcome Collection. Source: Wellcome Collection.
![no text alternative](https://iiif.wellcomecollection.org/image/V0003228/full/800%2C/0/default.jpg)
Licence: Public Domain Mark
Credit: Gustav Robert Kirchhoff. Wood engraving. Wellcome Collection. Source: Wellcome Collection.