10 STUDIES IN GENERAL PHYSIOLOGY 
On either side of the spectrum the animals remained at rest. 
In addition to this, Bert made another experiment. He 
had a spectrum projected on a trough, and observed how 
the animals distributed themselves over the different parts 
of the spectrum. 
L’immense majorité se placa dans le jaune, le vert, l’orange; 
une assez grande quantité se voyaient encore dans le rouge, un 
certain nombre dans le bleu, quelques-unes de plus en plus rares & 
mesure qu’on s’éloignait dans les régions plus réfrangibles du 
violet, au dela du rouge, au dela de l’ultra-violet; dans les régions 
invisibles, en un mot, on n’en trouvait que d’isolées en promenade 
accidentelle. 
From these facts Bert concluded that Daphnia behaves 
in the spectrum much as a man would, who, when reading a 
book, would move into the brightest part of the spectrum, 
into the yellow light. 
Lubbock repeated Bert’s experiment on Daphnia.’ One- 
half of a dish was covered by a yellow screen; the other 
half was left uncovered. In the uncovered half 1,904 
animals collected, while 3,096 gathered under the yellow 
screen. From this Lubbock concludes that Daphnia has a 
“preference”’ for ‘‘yellow.” But one would suppose that in 
the uncovered part of the dish there was at least as much 
yellow light as under the yellow screen; or did the majority 
“hate” the blue light? 
When Lubbock covered one-half of the trough with 
blue glass and left the other uncovered, he found 2,046 
animals under the blue glass, and 2,954 in the uncovered 
part of the trough. Whether one is to conclude from this 
that blue light is in the sense of Lubbock “disagreeable” to 
Daphnia is not stated. When half of the trough was 
covered with red glass, there collected 1,928 animals under 
the red glass, while 3,072 collected in the uncovered por- 
1 Lussock, “Die Sinne und das geistige Leben der Thiere,”’ Internationale 
wissenschaftliche Bibliothek, Vol. LXVII (1889). 
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