LIVING MATTER 67 



tons of energy are liberated in consequence of 

 the pull of a few inch-grains on the trigger, or 

 to an indefinitely small push which makes 

 electric contact : the energy set free is that 

 which is stored up in the charge." * 



Thirdly, the amoeba may be observed to feed Assiraila- 

 and this it does by putting forth processes of tlon 

 its body wherewith it surrounds any particle 

 of food which may be in the water around. 

 Having accomplished this it then dissolves the 

 particle or such portions thereof as are avail- 

 able for its purpose, utilises the dissolved 

 material for the re-building of its tissues and 

 the replenishment of the energy which it has 

 expended in its various actions and casts out 

 the useless refuse from its body. In some 

 manner or another all living bodies^ and alL 

 living cells must be fed; must change their 

 food into the materials suitable for their own 

 use and must get rid of waste and superfluous 

 portions. In this brief statement is included 

 the whole vast science of physiological chemis- 

 try, even to glance at which would be impos- 

 sible in this book. Speaking in the most Metabolism 

 general manner it may be said that these 

 metabolic changes, as they are called, are of 

 two kinds. On the one hand less complex and 

 more stable substances are built up into other 

 * Hartog. 



