62 LEISURE-TIME STUDIES, 



actually imitate the experiment performed of old by that 

 redoubtable demi-god Hercules; since, by the artificial divi- 

 sion of our polype, we may give origin to new beings, and 

 may multiply the species through the destruction of a single 

 individuality. These curious results, also obtained by expe- 

 rimentation on the sea-anemones, were first made known to 

 the world at large by Trembley, an Englishman, who was 

 tutor to the two sons of Count Bentinck, and who, whilst 

 resident at Geneva about the middle of last century, con- 

 trived to find time and opportunity for experimentation upon 

 these polypes. In 1744 Trembley published his memoir on 

 the hydra, and we shall leave the ingenious naturalist to 

 detail in his own language the method and results of his 

 experiments. Surprised at the curious life-history and 

 plasticity of these creatures under almost every condition, 

 Trembley resolved to ascertain if the reproductive powers of 

 hydrse were further allied to those of plants, in their ability to 

 reproduce their like by being divided into " slips." Having 

 divided a hydra crosswise, and nearer to the mouth than to 

 the root-extremity, he put " the two parts into a flat glass, 

 which contained water four or five lines in depth, and in 

 such a manner that each portion of the polyp could be 

 easily observed through a strong magnifying glass. . . . On 

 the morning of the day after having cut the polyp, it seemed 

 to me that on the edges of the second part, which had 

 neither head nor arms, three small points were issuing from 

 these edges. This surprised me extremely, and I waited 

 with impatience for the moment when I could clearly ascer- 

 tain what they were. Next day they were sufficiently 

 developed to leave no doubt on my mind that they were 

 true arms. The following day two new arms made their 

 appearance, and some days after a third appeared, and 

 I now could trace no difference between the first and second 

 half of the polyp which I had cut." 



Experimenters, since Trembley's time, but following in 

 the track of that ingenious observer, have cut and divided 

 the hydra in almost every possible fashion, with the result of 



