of a Stomach in VegetaJs. 283 



in plants ; nor more so in the one than in the other : let an 

 example from either reign suffice for illustrations. 



Take the freshwater polype (Hydra viridis or grisea) a 

 small lump of translucent jelly, about the size of a pea when 

 contracted, but when extended, and viewed under favourable 

 circumstances, lengthened in its body to about three-quarters 

 of an inch, and more resembling the finger of a small glove, 

 with a few ravelings round the edge, than any other familiar 

 figure. This creature possesses neither wings nor legs, nor 

 any of the ordinary organs of progression ; it is apparently 

 homogeneous in its structure, shewing not even a rudiment 

 of bone for leverage, or a semblance of muscle for contrac- 

 tion, and yet it protrudes and withdraws its tentacles, moves 

 from leaf to leaf, travels from plant to plant, from stone to 

 stone, quits (he dark and approaches the light side of the 

 vessel in which it may be kept, basks in the sun-beams, 

 enjoys the warmth of summer, becomes torpid during cold 

 weather, and hybemates like the tortoise or the dormouse ; 

 retreats if touched, defends itself when attacked, and often 

 attacks in turn ; pursues its prey with avidity, and, although it 

 has neither tongue, nor teeth, nor palate, yet with hungry relish 

 it devours the minute animalcules it can catch ; nay, even with 

 cannibal propensities, will force smaller or weaker individuals 

 of its own species into its simple pouch or stomach, digest a 

 part, and then reject the faeces by that single aperture which 

 is both entrance and exit, both mouth and vent to this gastric 

 prototype, which thus absorbs a part of its ingested food and 

 vomits up the rest ; such being the natural process in this sim- 

 ple being, to which the higher grades return in many cases of 

 disorder or disease. And yet so finely does this prima com- 

 munis via participate in the peculiarities of digestion, and 

 acknowledge its general laws, that, like the animal stomach of 

 the highest grade which will digest a bone when dead, but can- 

 not act on a pulpy worm when living, this pouch can only feed 

 on prey that has been truly killed. Trembley, I think, it was 

 who observed two hungry polypes fighting which should become 

 the other's meal ; or perhaps the little one endeavouring to 

 escape, the greater attempting to devour the less : strength, 

 however, at last prevailed, and this Saturnian polype swallowed 

 OCT.— dec. 1829. U 



