THE EFFECT OF COLOURED LIGHT ON ANIMAL LIFE.

Thames Star, Volume X, Issue 3206, 29 May 1879, Page 4

THE EFFECT OF COLOURED LIGHT ON ANIMAL LIFE.

Owing to the numerous experiments of which; plants have been the object, we now know that the different coloured rays of the solar lijjht have a particular action on the processes of the nutrition of those organised beings. As to their effect oh the development of animals, the researches •re far less numerous and complete!'"iM 1;; Beclard, had made some experiments with the different parts of the spectrum on the eggs of the fly (Musca carnaria), and found that they hatched much more quickly : under the violet and blue rays than under the green. M. Yung has for three years beeninvestigating this subject at Zoological Laboratory at Eoscoff (Brittany). Three series of observations were made on the eggs of the Edna temporaria, the. trout {Salmo trutta), and the Lymnea kafrrialis. Other conditions being identical* the eggs were subjected, in separate portions to different//coloured lights. One vase of each was kept in a dark cupboard. The . conclusions, identical in each case, were as follows:—1. The different coloured rays of solar light act in varied ways on the development of the eggs. 2. The violet light hastens the hatching in a very remarkable manner, and is very closely followed in that; respect by the blue, then by the yellow and the white. 3. The red and green rays appear injurious, in this sense, that, under their influence, complete development of the eggs was never obtained. 4 Darkness does not prevent the development, although it delays it considerably. 5. The various parts of the spectrum may be thus arranged in their effect on development in the following decreasing order:—Violet, blue, yellow and white (almost identical), darkness, red and green (prevent development) ; 6, the tadpoles of frogs, of the same size and previously existing tinder precisely similar conditions, deprived of all nourishment, died much quicker of inanition in the violet and blue irays than the others, because they consumed more rapidly their accumulated alimentary; 7, the mortality appeared greater in the coloured lights than white. However, that point is not so certain, and requires farther investigation before pronouncing a positive decision.