50 MARVELS OF PONU-LIFE. 



exhibit the wonderful nature of animal life. Their 

 bodies are composed of a uniform substance, called 

 sarcode^ in which is embedded a colouring matter 

 resembling that in the leaves of plants; every part 

 possesses irritability and contractility, and they are 

 very sensitive to the stimulus of light. They may be 

 cut and grafted like trees, and if turned inside out, 

 the new inside digests and assimilates as well as the 

 old. Whether any form of consciousness can belong 

 to creatures which have no distinct nervous system^ 

 is open to dou1)t, but it would seem probable from 

 their movements that food and light afford them 

 something like a pleasurable sensation in a very 

 humble degree. If we were sufficiently acquainted 

 with the secrets of molecular combination we might 

 discover that the various functions of these simple 

 organisms were discharged by different particles^ 

 although it is only in higher creatures that muscular 

 particles are aggregated into muscles, or nerve par- 

 ticles into nerves. 



Having examined the general appearance and 

 proceedings of the hydra, let us cut off a tentacle, 

 or take a small specimen and gently crush it by 

 pressing down the cover of the live box, and place 

 the object so prepared under a power of about 

 three hundred linear. If we then illuminate it with 

 a moderate quantity of oblique light, we shall dis- 

 cover round the edge of the tentacle a number of 



