1. Strychnine, treated with sulphuric acid and potassic dichromate (violet). 2. Brucine, treated with potassic nitrate and sulphuric acid (clear red). 3. Quebrachine, treated with vanadium sulphate (dark blue). 4. Quinine, Vogel’s reaction (red). 5. Caffein, Murexid reaction (violet-red). 6. Dephinoidin, Froehde’s reagent (cherry-red). 7. Veratrine, treated with sulphuric acid (straw-yellow). 8. „ „ „ (cherry-red). 9. „ „ „ (carmine-red). 10. Veratrine, Furfurol reaction (blue-violet). 11. Sabadillin, treated with sulphuric acid (red). 12. Veratroidine, „ „ (brown-red). 13. Jervine, Furfurol reaction (blue). 14. Sabadine, „ „ (blue). 15. Sabadine, treated with sulphuric acid (cherry-red). 16. Physostigmine, „ „ (grass-green). 17. Morphine, treated with Froehde’s reagent and sugar (dark-green). 18. Narcotine, treated with a mixture of sulphuric acid and nitric acid (30 drops of sulphuric to 1 drop of nitric), (red). 19. Codeine, treated with Froehde’s reagent and sugar (dark violet). 20. Papaverine, treated with Froehde’s reagent (green-blue). 21. Sanguinarin, „ „ (violet-red). 22. Chelidonin, „ sulphate of vanadium (dark green). 23. Solanin, „ sulphuric acid and allowed to stand 4 hours (brown-red). 24. Digitalin, „ Erdmann’s reagent (red). 25. Aniline, „ sulphuric acid and potassic dichromate (blue).] The wave lengths corresponding to the numbers on the scale in the diagram are as follows:-- W.L. 0 732 1 656 2 589·2 3 549·8 4 510·2 5 480·0 6 458 7 438 Examination of Blood, or of Blood-Stains.