20 HABITS OF WORMS. Chap. L 



persons have found no difficulty in observing 

 worms at niglit by the same means.* 



Hofifmeister, however, states f that worms, 

 with the exception of a few individuals, are 

 extremely sensitive to light ; but he admits 

 that in most cases a certain time is requisite 

 for its action. These statements led me to 

 watch on many successive nights w^orms kept 

 in pots, which were protected from currents 

 of air by means of glass plates. The pots 

 were approached very gently, in order that 

 no vibration of the floor should be caused. 

 When under these circumstances worms were 

 illuminated by a bull's-eye lantern having 

 slides of dark red and blue glass, which in- 

 tercepted so much light that they could be seen 

 only with some difficulty, they were not at all 

 affected by this amount of light, however long 

 they were exposed to it. The light, as far 

 as I could judge, was blighter than that from 

 the full moon. Its colour apparently made 

 no difference in the result. When they were 



* For instance, Mr. Bridgman and Mr. Newman (* The 

 Zoologist/ vol. vii. 1849, p. 2576), and some friends who observed 

 worms for me. 



t * Familie der Regenwiirmer,' 1845, p. 18. 



