HYDRA'S TENACITY OF LIFE. 



PART III. 



As the whole animal is nourished from the surface of 

 the digestive cavity, they appear to suffer no incon- 

 venience from being turned inside-out, the new cavity 



performing all the func- 

 tions of digestion as well 

 as the old one. They may 

 be cut into any number 

 of pieces, and, after a little 

 ft*, time, each piece becomes 

 J a perfect Hydra. The head 

 I may be cut off and they 

 get a new one ; or it may 

 be split into two or three 

 parts or more, and the 

 animal becomes many- 

 headed ; and, what is still 

 more marvellous, two 

 Hydrse may be grafted 

 together direct, or head 

 and tail, and they com- 

 bine into one animal. 



These singular and vo- 

 racious creatures increase 

 like plants by budding. A 

 little protuberance rises 

 on the body by the 

 bulging out of the double 

 skin or wall, so that the 

 interior of the bud is a 



clear cavity in communication with the stomach of 

 the Hydra (fig. 110, 6). The bud increases in length, 

 opens at its extremity into a mouth, and gradually 

 acquires the size and form of its parent (fig. 110, c) ; 

 the communication is then by -degrees closed, and at 

 last the matured bud drops off and becomes an inde- 

 pendent Hydra. Dr. Carpenter observed that this pro- 



Fig. 110. Hydra fusca. 



