Appearance often differs from reality. 



living forms from ova, the ultimate form produced 

 does not exist in the germ, any more than a crystal 

 exists in its solution, but is a natural consequence of 

 the forces acting in and upon the germ, like the 

 cubical form of a crystal of common salt is a result of 

 the forces acting in its constituents under the con- 

 ditions of its environment, especially those of pressure 

 and temperature. The extent to, and manner in 

 which, the force and principle operate, depend upon 

 the material substance, and its conditions internal 

 and external. 



It is a common circumstance, both in physical, 

 mental, and moral subjects, for the apparent to be 

 the very opposite of the real. This general truth has 

 been repeatedly illustrated in an incidental manner in 

 this book, and need not be much further elucidated. 

 Phenomena are none the less real, however, because 

 they are not readily manifest ; our earth is as much 

 tied to the sun by the invisible power of gravity, as if 

 it was attached to it by visible material chains. Mis- 

 taking the apparent for the real, largely explains the 

 persistency of certain beliefs, and why it is that per- 

 sons unacquainted with science, cling to self-decep- 

 tion, and resist some of the most firmly established 

 truths. The more evident but untrue explanation is 

 believed, whilst the less apparent but true one is 

 rejected. It is the chief cause of the belief that " the 

 will is a supernatural power." To a scientific man 

 however, apparent contradictions are not unfrequently 

 a sign of truth ; too accurate results sometimes indi- 



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