HYDRA. 81 



killed by the touch of the Hydra. Yet the 

 Hydra is not vicious, and kills only when it needs 

 food, and then in the easiest possible way killing 

 the worm outright, and numbing other animals so 

 that they suffer not. Although so destructive 

 when in want, it is very tolerant of other creatures 

 which it does not require for food especially so to 

 a small infusorian, great numbers of which are 

 often seen swarming over it, and are apparently 

 supported by what they get as parasites off its 

 tentacles and body. 



We have seen how the Hydra may be propa- 

 gated by cuttings, and it may be here noted, that 

 those thus produced are generally the finest, as is 

 the case in so many other of the lower forms of life. 

 The general method is by budding. A slight pro- 

 tuberance will appear anywhere indifferently on the 

 side of its body, which gradually grows into a bud, 

 and thence into a young Hydra exactly like its 

 parent, to which it will remain attached for an 

 indefinite time : indeed, if undisturbed, a second 

 and even third generation will thus be formed, 

 Hydra budding on Hydra, before a detachment 

 is effected. The young thus produced eventually 



