110 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vor. VILE 
about excitedly until they reached the shady portion, when they became 
motionless again. Red, yellow, and green rays did not affect them, blue 
light alone provoked as rapid action as compound light.. In this case the 
exact time in seconds which elapsed before movement occurred after 
exposure to the coloured light was carefully noted, likewise the possible 
effects of higher or lower temperature of the wate’. The great value of 
these experiments, as pointed out by Finsen, lay in the fact that sala- 
manders of this age rarely move at all, without a violent external cause. 
The strength of light used, and the quality of the glass as to the rays 
which would pass through certain shades were carefully noted also. The 
latter is a factor frequently neglected by experimenters; the glass in this 
case was examined spectroscopically, in order to be positive. 
When tadpoles were kept in the shade for some weeks, it was noted 
that they became very lively when exposed to daylight when the water 
was changed. Another interesting point was noted; a number of tadpoles 
had been raised from eggs which had been kept under light of different 
colours, but all received daylight every twenty-four hours, when the water 
of the aquarium was changed, at which time those raised in red light 
became very excited because unaccustomed to light, while those raised 
under blue light were quite indolent. 
The experiments with the earthworms, placing them in an oblong 
box, with a lid of glasses, red, yellow, green, and blue, were repeated and 
varied by turning the cover after the worms had gathered at the dark end, 
thus exposing them to different strengths of light, but always with the 
same result, namely, the worms were uncomfortable in and avoided the 
blue light and sought the,red. Some worms that were kept for feeding 
the salamanders met with an accident, some died and some were very 
weak; to save as many as possible various expedients were resorted to, 
such as moistening them, but without result. On exposure to direct sun- 
light, three or four began to react and recovered. 
Experiments with the earwig (forficula) in the box with the glass 
cover quickly showed their desire to avoid the blue light. Thus, ‘‘when 
on turning the cover, the blue light fell upon the animals, their extraordi- 
nary evolutions were curious to watch. Their antenne began to vibrate, 
the animals at once became restless, running to all sides, until they finally 
came to rest under the red glass. The experiments were frequently 
repeated, and at last the adults seemed to understand the situation, for 
after several changes of the light, they no longer mistook the road, but made 
off without hesitation towards the red light.’’ Woodlice (oniscus) and 
beetles (pterostichus) placed in the box behaved as did the earwigs. 
