ORIGIN OF THE ANIMATED TRIBES. 101 



be inquired into. The predominant idea hitherto has been, 

 that the vital affinities are of a totally distinct nature, de- 

 pending upon a mystic something, to which the term vital 

 principle was applied. But this idea is now on the decline. 

 Admitting the vital affinities, as powers superseding and 

 counteracting ordinary chemical affinities, it is seen that the 

 idea of a distinct inscrutable principle on which they depend, is 

 " both unsupported by evidence and useless in the explanation 

 of facts." ( 45 ) It is becoming evident that living structures 

 result from the action of a multitude of natural forces in 

 combination "gravity, cohesion, elasticity, the agency of 

 the imponderables, and all other powers which operate both 

 on masses and atoms." Professor Draper, of New York, in 

 making this statement, says " It is astonishing that in our 

 days the ancient system which excludes all connexion with 

 natural philosophy and chemistry, and depends on the ficti- 

 tious aid of a visionary force, should continue to exist ; a 

 system which at the outset ought to have broken down by 

 the most common considerations, such as those connected 

 with the mechanical principles involved in the bony skeleton, 

 the optical principles in the construction of the eye, or the 

 hydraulic action of the valves of the heart."( 46 ) 



So much for the combinations concerned in living bodies ; 

 but how shall we hope to see their forms brought under any 

 relation to physical laws ? On this point we have some 

 illustrations in the phenomena attending the production of 

 crystals, a class of bodies which has been said to stand be- 

 tween the inorganic and the organic. From the agency which 

 has been employed by Mr. Crosse in making crystals formerly 

 supposed to be of Nature's production alone, it is now incon- 

 testable that crystallization is dependent on electric agency, 

 the special forms being the result of the peculiar nature of the 

 constituent substance and the conditions under which the 

 imponderable is applied. Here are obviously natural means 

 of producing forms almost as various as those of living beings, 

 and equally determinate and regular. A certain community 

 of cause in the two instances is indicated by the surprising 

 resemblance which some examples of crystallization bear to 



