Along with his anatomical duties, Welcker was also a specialist in the fields of anthropology, ethnology, microscopy and biology. He published numerous articles on each of these subjects. In 1854 he devised a method for measuring blood volume in humans and animals. He also devised a method for measuring red blood cell volume. The eponymous "Welcker's angle" is named after him, which is the anterior, inferior angle of the parietal bone.
He is also credited with starting the first study of the persistence of friction ridge skin over time. He recorded his right hand print in 1856 and 1897, publishing a study in 1898.[1]
In 1889 Welcker received a patent for the invention of "galvanic spectacles", which were essentially battery-operated eyeglasses with nosepiece electrodes.[2] These glasses were used as a remedy for nasal congestion. In addition he conducted numerous studies of human skulls, including the famous skulls of Dante Alighieri and Friedrich Schiller.
References
^Wilder, H. H. and Wentworth, B. Personal Identification; The Gorham Press: Boston, 1918, pp. 339–340. Online reference to this work at: http://www.ncjrs.gov/pdffiles1/nij/225321.pdf (Page 1-6 or search Welcker)