540 BULLETIN OP THE 



ammonia,) to the vegetable plane of power, introduces naturally 

 the consideration of the still higher elevation of vegetable or- 

 ganic matter to the animal plane of power. "As in the case of 

 the seed of the plant, we presume that the germ of the future- 

 animal pre-exists in the egg ; and that by subjecting the mass to 

 a degree of temperature sufficient perhaps to give greater mobility' 

 to the molecules, a process similar in its general effect to that 

 of the germination of the seed commences. . . . During this 

 process, power is evolved within the shell, we cannot say in the 

 present state of science under what particular foi*m ; but we are 

 irresistibly constrained to believe that it is expended under the 

 direction again of the vital principle, in re-arranging the organic 

 molecules, in building up the complex machinery of the future 

 animal, or developing a still higher organization, connected with 

 which are the mysterious manifestations of thought and volition. 

 In this case as in that of the potato, the young animal as it 

 escapes from the shell, weighs less than the material of the egg^ 

 previous to the process of incubation, The lost material in this 

 case as in the other, has run down into an inorganic condition by 

 combining with oxygen, and in its descent has developed the 

 power to effect the transformation we have just described." 

 The consumption of internal power does not however stop 

 with the development of the young animal, as it does in the 

 case of the young plant. " The young animal is in an en- 

 tirely different condition : exposure to the light of the sun is not 

 necessary to its growth or its existence : the chemical ray by 

 impinging on the surface of its body does not decompose the car- 

 bonic acid which may surround it, the conditions necessary for 

 this decomposition, not being present. It has no means by itself 

 to elaborate organic molecules ; and is indebted for these entirely 

 to its food. It is necessary therefore that it should be supplied 

 with food consisting of organized materials ; that is of complex 

 molecules in a state of power. . . . The power of the living ani- 

 mal is immediately derived from the running down of the com- 

 plex organized molecules of which the body is formed, into their 

 ultimate combination with oxygen, in the form of carbonic acid 

 and water, and into ammonia. Hence oxygen is constantly 

 drawn into the lungs, and carbon is constantly evolved. . . . 

 The animal is a curiously contrived arrangement for burning car- 

 bon and hydrogen, and for the evolution and application of power. 

 A machine is an instrument for the application of power, and 

 not for its creation. The animal body is a structure of this 

 character. ... A comparison has been made between the work 

 which can be done by burning a given amount of carbon in 

 the machine — man, and an equal amount in the machine — steam- 

 engine. The result derived from an analysis of the food in one 

 case, and the weight of the fuel in the other, and these compared 

 with the quantity of water raised by each to a known elevation, 



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