THE SPIDERS 165 



must be other powers at play in the tiny animal's 

 machinery. 



Total abstinence from food could be understood, if 

 it were accompanied by inertia: immobility is not life. 

 But the young Lycosae, though usually quiet on their 

 mother's back, are at all times ready for exercise and 

 for agile swarming. When they fall from the maternal 

 perambulator, they briskly pick themselves up, briskly 

 scramble up a leg and make their way to the top. It is 

 a splendidly nimble and spirited performance. Besides, 

 once seated, they have to keep a firm balance in the mass ; 

 they have to stretch and stiffen their little limbs in order 

 to hang on to their neighbors. As a matter of fact there 

 is no absolute rest for them. Now physiology teaches 

 us that not a fiber works without some expenditure of 

 energy. The animal, which can be likened, in no small 

 measure, to our industrial machines, demands, on the one 

 hand, the renovation of its organism, which wears out 

 with movement, and, on the other, the maintenance of 

 the heat transformed into action. We can compare it 

 with the locomotive-engine. As the iron horse performs 

 its work, it gradually wears out its pistons, its rods, its 

 wheels, its boiler-tubes, all of which have to be made 

 good from time to time. The founder and the smith 

 repair it, supply it, so to speak, with " plastic food," the 

 food that becomes embodied with the whole and forms 

 part of it. But, though it has just come from the 

 engine-shop, it is still inert. To acquire the power of 

 movement it must receive from the stoker a supply of 

 " energy-producing food " ; in other words, he lights a 



