Fig. 5.

External aspect of mice bearing a developed mouse melanoma untreated (a) or treated (b–d) for 7 days with the immunotoxin. Tumours were sectioned and stained with haematoxylin–eosin (e–h). In the immunotoxin-treated mice, the tumours were necrosed and a hardened and fibrous material accumulated in that area. a, e Tumours from untreated animals. b, f Apparent complete remission of tumours. c, g Large but incomplete remission of tumours. d, h Slight remission of tumours. Scale bar: 5 mm