100 DECOMPOSITION AND NUTRITION. 



Therefore, if we may have, and do have, as no one doubts, an 

 animal substance in a peculiar state, such as we find in the 

 bird's egg, dependent upon physical forces for its development 

 into an active being, is it illogical to suggest that we may pos- 

 sibly have some other peculiar form or state of animal substance 

 which physical forces, in the hands of a great controlling power, 

 can develop into life ? What is digestion but a rapid method 

 of decomposing animal (or vegetable) matter, and recornposing 

 it directly into living' tissues ? Now, among the lower animals, 

 there are certain kinds which, in a physiological sense, do not 

 digest their own food. The Tape - worms which live in the 

 various organs, stomach, intestine, liver, and brain, of animals, 

 although some have more or less traces of a digestive organ, 

 and others none at all, as I have shown you, (p. 83,) do not 

 prepare their own food, but absorb it directly through the skin 

 of the body, just as a sponge soaks up water. The food is pre- 

 pared for them by the animals in which they live ; and they 

 merely appropriate the decomposed substance which surrounds 

 them. 



But it is not even necessary that the decomposed food should 

 be prepared by digestion in other animals; for flesh which is 

 decomposed by decay into a semi-fluid mass is absorbed by the 

 sponge-like bodies of certain animals which live in stagnant pools. 

 In fact, we have all possible degrees in the mode of nutrition of 

 living beings, from that in man, in whom the digested fluid is car- 

 ried from the stomach to all parts of the body in distinct tubes, 

 the blood-vessels, down to that in the lowest animals, in which 

 there are no vessels whatever, and in which the nutritive sub- 

 stance percolates through the interstices of the body. 



In these lowest animals the process of transforming decom- 

 posed matter into their living substance is reduced to the most 

 simple transition from death unto life that can be conceived. 

 On the one side is the Amoeba, consisting of a mere jelly-like, 

 porous mass, and on the other side is its food, a decomposing 

 substance, in some form scarcely less simple than itself. What 



