Die Histopathologie der Hautkrankheiten.

This monumental work is a landmark in dermatological history. Sir Norman Walker translated it into English in 1896. Unna, short in stature but a giant among dermatologists, initiated the study of the skin by means of diascopy and gave several original descriptions of affections of the skin. The acne bacillus is described for the first time on p. 357.