Vegetable juices, treated in this way, offer very striking examples of the above effects. The colouring-matter of turmeric, annotto, dyer's saffron,[2] and other vegetables, being extracted with spirits of wine, exhibits tints of yellow, yellow-red, and hyacinth-red; these, by the admixture of alkalis, pass to the culminating point, and even beyond it to blue-red.
No instance of a culmination on the minus side has come to my knowledge in the mineral and vegetable kingdoms. In the animal kingdom the juice of the murex is remarkable; of its augmentation and culmination on the minus side, we shall hereafter have occasion to speak.
[1] Culmination, the original word. It might have been rendered maximum of colour, but as the author supposes an ascent through yellow and blue to red, his meaning is better expressed by his own term.
[2] Curcuma, Bixa Orellana, Carthamus Tinctorius.