Any living creature exposed to the rays of a sun, which is certain to emit some chemical rays, is subject to coloration as a protection against those rays.
Of course copper would also yield a brown coloration, but I am supposing that the circumstances preclude the presence of copper.
This coloration of the milk is due to the growth of microscopic organisms.
We have always observed this acid reaction in the juices of plants with red or rose-red coloration, while the blue juices of plants have always exhibited an alkaline reaction.
When this condition is arrived at, an additional drop of nitric acid causes no dark coloration.
The results show a strong object-hole effect similar to the one of the watercolor illusion and a coloration effect similar to the purple only condition.
The coloration is nearly absent with 5 contours.
Coloration was common enough in fourteenth-century motet tenors, but is rarely found in isorhythmic tenors after c. 1400.
