96 THE MECHANICAL FUNCTIONS. 



§ 4. Animal Oi'^anization. 



The structures adapted to the purposes of vege- 

 table life, which are limited to nutrition and 

 reproduction, would be quite insufficient for the 

 exercise of the more active functions and higher 

 energies of animal existence. The power of 

 locomotion, with which animals are to be invested, 

 must alone introduce essential differences in their 

 organization, and must require a union of 

 strength and flexibility in the parts intended 

 for extensive motion, and for being acted upon 

 by powerful moving forces. 



The animal, as well as the vegetable fabric is 

 necessarily composed of a union of solid and 

 fluid parts. Every animal texture appears to be 

 formed from matter that was originally in a 

 fluid state ; the particles of which they are com- 

 posed having been brought together and after- 

 wards concreting by a process, which may, by a 

 metaphor borrowed from physical science, be 

 termed animal crystallization. Many of those 

 animals, indeed, which occupy the lowest rank 

 in the series, such as Medusce, approach nearly 

 to the fluid state ; appearing like a soft and 

 transparent jelly, which by spontaneous decom- 

 position after death, or by the application of 



