HYDRID&. 121 



The third and most extraordinary mode of reproduction in the 

 polyps has been discovered by Trembley in the case of the green 

 Hydra. So surprised was this naturalist at the strange anomalies 

 which surround these creatures, that he began to have doubts, and 

 gravely to ask the question, is this polyp an animal? or, is it a 

 plant ? 



In order to escape from this state of indecision, it occurred to 

 him to cut a Hydra into pieces. Concluding that plants alone could 

 reproduce themselves by slips, he waited the result of the experiment 

 for the conclusion he sought. On the 25th of November, 1740, he 

 cut a polyp into sections. " I put," he tells us, " 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. It will suffice to say 

 that I had cut the polyp transversely, and a little nearer to the 

 anterior. 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 ascertain 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 could now trace no difference between the first and second half of 

 the polyp which I had cut." 



This is assuredly one of the most startling facts belonging to 

 natural history. Divide a fresh-water polyp into five or six parts, 

 and at the end of a few days all the separate parts will be organised, 

 developed, and form so many new beings, resembling the primitive 

 individual. Let us add, that the polyp which should thus have lost 

 five-sixths of its body, the mutilated father of all this generation, 

 remains complete in itself; in the interval, it has recuperated itself 

 and recovered all its primitive substance. 



After this, if a Hydra vulgaris wishes to procure for itself the 

 blessings of a family, it has only one thing to do : cut off an arm ; 

 if it desire two descendants, let it cut the arm in two parts ; if three, 

 let it divide it into three ; and so on ad infinitum. " Divide one of 

 the animals," says Trembley, " and each section will soon form a new 

 individual in all respects like the creature divided." " A whole host of 

 polyps hewn into pieces," says Fre'dol, "will be far from being 

 annihilated." " On the contrary," we may say, in our turn, " its 

 youth will be renewed, and multiplied in proportion to the number of 



