Slide showing tinted diagram of the larva of Rana esculenta which has had the same operation as in Fig. 39. Slide shows tinted diagram of the larva of Rana esculenta which has had the same operation as in Fig. 39. The left third of the larva is tinted red. Title below image reads 'Fig. 40. the same operation as in Fig. 39, the larva of Rana esculenta. The transplanted skin of the trunk has not formed the slightest indication of a lens. (After Spemann, 1912a).' Late 19th to early 20th century