REACTIONS TO LIGHT IN PLANARIA MACULATA GG 
specimen was then illuminated laterally with stronger light, viz., 
75 meter-candles, the animal bent its body in the region just 
posterior to the cephalic lobes, thus turning the anterior end 
sharply away from the light. The point of bending occurred 
somewhat farther back (fig. 6, 6) when the animal was subjected 
to a lateral illumination of 208 m.c. When the lateral illumi- 
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Fig. 6 Diagram representing orientation of planarians in different illumina- 
tions. Arrows indicate the direction of light. A, path of specimen in 52 meter- 
candles; B, path of specimen in 208 m.c.; 1, 2, successive positions of specimen; C, 
path in 3328 m.c., 1, 2’, 3’, successive positions of specimen. 
nation was increased to 3328 m.c., the bending occurred in the 
region of the pharynx, but first toward and then away from the 
light, and the reactions were very violent (fig. 6, C). 
These observations on the character of turning in specimens 
under the influence of increasing intensities of light are interesting 
when considered in relation to the nature of the nerve impulse 
from the eye to the musculature which causes the bending. When 
