230 NATURE AND LIFE. 



and undertook experiments. " Having an opportunity," 

 he says, " to examine the shores of the ocean, which are 

 crowded with a vast number of crabs, a creature something 

 of the nature of crawfish, I could not escape the suspicion 

 that philosophers were wrong in this matter, and common 

 people right." Reaumur took lobsters and crabs, removed 

 one or several of their limbs, and shut up the creatures so 

 mutilated in reservoirs communicating with sea-water. At 

 the end of a few months he was astonished to find that 

 new legs had taken the place of those that had been re- 

 moved. He repeated his experiments with crawfish also, 

 and described, with the precision which has given him re- 

 nown, the mechanical method of these new growths. 



Thirty years later, Abraham Trembley, while walking 

 near a lake at the Hague, remarked in it certain fine green 

 filaments, provided with appendages, and looking like vege- 

 tables. To learn whether he was really dealing with plants, 

 he cut one of them into several bits. The separated parts 

 soon reproduced each a complete whole, and these individ- 

 ual wholes moved, changed their place, and seized insects 

 with their arms to carry them into their digestive cavities. 

 They were fresh-water polyps, true animals. Trembley 

 learned that, when one of these polyps was cut in two, the 

 head reproduced the tail, and the tail the head. He cut 

 two of them lengthwise, and joined them in a graft ; in- 

 stead of a polyp with eight arms, he had one with sixteen. 

 A short time afterward Charles Bonnet repeated Trembley 's 

 experiments on the reproduction of the polyp, and tried 

 others on a fresh-water worm called the naiad. He re- 

 marked that this worm, like the polyp, grows again those 

 of its parts that are removed. He made like trials with 

 the earthworm, and proved to his great astonishment that 

 this highly-complex animal, which has so many rings, with 

 delicate locomotive organs attached to each ring, which 

 has, too, digestive and generative systems, etc., possessed 



