170 NATURAL HISTORY. 



either thrive or languish according to the wholesome or 

 hurtful application of these stimulants. The spontaneous 

 movements of plants are almost as readily to be observed as 

 their living principle. The general direction of their branch- 

 es, and especially of the upper surface of their leaves, though 

 repeatedly disturbed, to the light, the unfolding and closing 

 of their flowers at stated times, or according to favourable 

 or unfavourable circumstances, with some still more cu- 

 rious particulars, are actions undoubtedly depending on their 

 vital principle, and are performed with the greater facility 

 in proportion as that principle is in its greatest vigour. Plants 

 alone have a power of deriving nourishment, though not in- 

 deed exclusively, from inorganic matter, mere earths, salts, 

 or airs, substances certainly incapable of serving as food for 

 any animals, the latter only feeding on what is or has been 

 organized matter, either of a vegetable or animal nature. So 

 that it would seem to be the office of vegetable life alone to 

 transform dead matter into organized living bodies. 



The Mineral kingdom can never be confounded with tho 

 other two. Fossils are masses of mere dead unorganized 

 matter, subject to the laws of chemistry alone ; growing in- 

 deed, or increasing by the mechanical addition of extraneous 

 substances, or by the laws of chemical attraction, but not 

 fed by nourishment taken into an organized structure. 

 Their curious crystallization bears some resemblance to or- 

 ganization, but performs none of its offices, nor is any thing 

 like a vital principle to be found in this department of na- 

 ture. If it be asked what is this vital principle, so essential 

 to animals and vegetables, but of which fossils are destitute, 

 we must own our complete ignorance. We know it, as we 

 know its omnipotent Author, by its effects. The infinitely 

 small vessels of an almost invisible insect, the fine and pel- 

 lucid tubes of a plant, all hold their destined fluids, convey- 

 ing or changing them according to fixed laws, but never 

 permitting them to run into confusion, so long as the vita! 

 principle animates their various forms. But no sooner does 

 death happen, than, without any alteration of structure, any 

 apparent change in their material configuration, all is re- 

 versed. The eye loses its form and brightness ; its mem- 

 branes let go their contents, which mix in confusion, and 

 thenceforth yield to the laws of chemistry alone. Just so it 

 happens, sooner or later, to the other parts of the animal as 



