358 RETROSPECT OF THE PRINCIPAL EPOCHS 



antiquity. The generality of this method of criticism has 

 especially contributed to shew on each occasion the boun- 

 daries of the several sciences, and to discover the weakness 

 of certain systems, in which unfounded opinions or con- 

 jectures assume the place of facts, and symbolising myths 

 present themselves as grave theories. Yagueness of lan- 

 guage, and the transference of the nomenclature of one 

 science to another, have conducted to erroneous views and 

 delusive analogies. The progress of zoology was long 

 endangered by its being believed that, in the lower classes 

 of animals, all the vital actions must be attached to organs 

 similar in form to those of the highest classes; and the 

 knowledge of the development of vegetation in what have 

 been called the Cryptogamic Cormophytes (mosses, liver- 

 worts, ferns and lycopodiums), or in the still lower Thallo- 

 phytes (sea weeds, lichens and fungi) has been still more 

 obscured, by the expectation of finding everywhere analo- 

 gies to the sexual propagation of the animal kingdom. ( 545 ) 

 If art and poetry, dwelling within the magic circle of the 

 imagination, belong rather to the inner powers of the mind, 

 the extension of knowledge, on the other hand, rests by 

 preference on contact with the external world; and this 

 contact becomes closer and more varied as the intercourse 

 between different nations increases. The creation of new 

 organs or nstruments of observation augments the intel- 

 lectual, and often also the physical powers of man. More 

 rapid than light, the closed electric current now carries 

 thought and will to the remotest distance. Forces, whose 

 silent operation in elementary nature, as well as in the 

 delicate cells of organic tissues, still escapes the cognizance 



