-113 - SENSE ORGANS. 



102. Gravity stimulus. Section of a pulvinus stained with iodine to show the 

 starch-grains lying on the lower side of each statocyst cell. 



CONDUCTION OF STIMULI. 



103. Light stimulus. Oat seedlings laterally illuminated, some with opaque 

 caps on the tips of the leaf-sheaths and others without such caps. Positive phototropic 

 curvature is shown only by those seedlings without caps, although the region of curvature 

 is seen to he below the region covered by the caps of the other seedlings. 



