218 SEA-SIDE STUDIES. 



which has a portion of its integument folded in, serving 

 both for mouth and stomach, but not anatomically differing 

 from the external integument, nor physiologically differing 

 in its action from that of the Amoeha's gelatinous sub- 

 stance ;* we then ascend to the Annelids having a real 

 intestine, lying free in the general cavity, but only mode- 

 rately, when at all, furnished with secretory apparatus ; and 

 so on, till at length we reach the Mammalia, with their 

 marvellously complex digestive apparatus. Corresponding 

 with this increasing complexity of the organs is the increas- 

 ing complexity of the food which the animals digest, from 

 simple gases up to meat. 



If all were not so marvellous in Nature, would not the 

 marvellous fact that food itself exists, arrest us ? Food is 

 what the organism can separate from the world around it, 

 converting what it separates into its own life. We may 

 consider Life itself as an ever-increasing identification with 

 Nature. The simple cell, from which the plant or animal 

 arises, must draw light and heat from the sun, nutriment 

 from the surrounding world, or else it will remain quies- 

 cent, not alive, although latent "svdth life ; as the grains in 

 Egyptian tombs, which, after lying thousands of years quies- 

 cent in those sepulchres, are placed in the earth, and then 



* Trcmbley turned a Hydra inside out, and found the outside perform the 

 function of a stomach. This has been held as proof that a mucus membrane 

 is only a reflection of the skin. But from what has been advanced in this 

 chapter, the reader may suspect that, inasmuch as the polype has no mucus 

 membrane whatever, the so-called stomach not being anatomically distinguish- 

 able from the external skin, and the process of digestion being wholly 

 mechanical, the current opinion is not proved by Trembley's experiment. 



