Slide showing engraving of a 'group of Echinococcus-heads'. Slide shows black and white engraving labelled 'Fig. 31 - a group of Echinococcus-heads, from an hydatid found in the liver of sheep. Maginfied about 25 diameters. From a drawing by Professor Busk.' Labelled at top of slide: 'Parasites and their hosts'. Small round sticker on upper right '12'. Late 19th - early 20th century