76 BIOLOGICAL LECTURES. 



both inert and inanimate. Each particle was imagined to be a 

 minute something created out of nothing. Its properties were 

 not inherent in it, but were imposed upon it, and might have 

 been different if the deity had so willed. Of the latter it is to 

 be said at the outset that physical philosophers have almost 

 always accepted their first principles from theologians and have 

 aimed to the best of their ability to interpret phenomena in 

 accordance with such assumptions. It was so in astronomy, 

 in geology, in physiology, in biology. Because no one ever 

 saw a stone or other so-called inanimate object roll up hill, or 

 do something which an animal might do, it was thought to be 

 unable to do anything, whereas every one knows and always 

 has known that it would roll down hill without any agency 

 different from its own ; also that one of the laws of motion 

 affirms that action and reaction are equal, and if one kicks such 

 a stone, it will kick back in return. Experience of each one of 

 us teaches the temerity of the action. A lump of coal and a 

 loaf of bread might lie in one place indefinitely long ; but would 

 that imply they were inert things and without energy or ability 

 to do anything? No; it would only imply that whatever energy 

 they might have would not show itself by a change of position 

 of the whole body. The loaf of bread is made up of particles 

 of carbon, hydrogen and oxygen with a trace of phosphorus, 

 sulphur, lime, and three or four other elements in less quantity 

 still. If eaten by an animal it will furnish it with energy for 

 doing various kinds of work. If fed to a steam engine in a like 

 manner it will raise weights or propel itself. If it furnislics 

 energy it must be because it has energy ; and if it has energy 

 it is not inert. In a like manner the lump of coal has energy, 

 for, if fed to a steam engine, it enables the latter to do its work. 

 If the lump weighs a pound it is capable of doing ten millions 

 of foot pounds of work, which, if applied to itself, would raise it 

 two thousand miles high. Can a body which possesses such an 

 amount of energy as that in any form be called an inert body ? 

 The trouble in thinking of such phenomena is here. Evidences 

 of energy have been looked for only in the ability of a body to 

 do a certain thing, namely, change its position. Let a man be 

 sleeping soundly and he does not change his position. If he is 



