Earth- Worms in History. 63 



As the sharply-pointed needles diverge somewhat, and as 

 several are drawn into the same burrow, each tuft forms a 

 perfect chcvaux-de-frise. Many tufts were pulled up in the 

 evening, but by the ensuing morning fresh leaves had taken 

 their places, and the burrows again well protected. Impos- 

 sible it would be to drag these leaves to any depth into the 

 burrows, except by their bases, as a worm cannot seize hold 

 of the two leaves at the same time, and if one alone were 

 seized by the apex, the other would be pressed against the 

 ground and resist the entry of the one that was seized. That 

 the worms should do their work well, it was very essential 

 that they drag the pine-leaves into their burrows by their 

 bases, that is, where the two needles are conjoined. But how 

 they are guided in this work was at first perplexing. The 

 difficulty, however, was soon settled. With the assistance of 

 his son Francis, the elder Darwin set to work to observe 

 worms in confinement during several nights by the aid of a 

 dim light, while they dragged the leaves of the afore- 

 mentioned kinds into their burrows. They were seen to 

 move the anterior extremities of their bodies about the leaves, 

 and on several occasions when they touched the sharp end 

 of the needle they suddenly withdrew as though they had 

 been pricked, but it is doubtful that they were hurt, for they 

 are indifferent to sharp objects, being known to swallow 

 rose-thorns and small splinters of glass. It may be doubted 

 whether the sharp end of the needle serves to tell them that 

 is the wrong end to seize, for the points of many were cut off 

 for the length of an inch, and these leaves were always drawn 

 in by their bases and not by the cut-off ends. The worms, 

 it seemed, almost instantly perceived as soon as they had 

 seized a leaf in the proper manner. Many leaves were 

 cemented together at the top, or tied together by fine thread, 

 and these in the majority of instances were dragged in by 

 their bases, which leads to the conclusion that there must 

 be something attractive to worms in the base of pine-leaves, 

 notwithstanding that few ordinary leaves are drawn in by 



