18 GENERAL CHARACTERS OF LIVING BEINGS. 



continually maintained by His superintending agency, without 

 which all would be anarchy and confusion. 



8. It would seem to be a part of the exercise of those laws, 

 that living beings should take from the inorganic world the mate- 

 rials of their structure, should convert these into parts of their 

 own fabric, should endow these with properties similar to those 

 which their previous structures possessed, and should even pro- 

 duce from them the germs of new structures, capable of perform- 

 ing the same changes. Thus, the germ contained in the seed 

 builds up the beautiful form and wondrous structure of the perfect 

 tree, with scarce any other materials than water and air ; and of 

 these it not only constructs its own stem, leaves, roots, and 

 flowers, but (what seems yet more extraordinary) it imparts to 

 its seeds, which, when separated from it and dried up, seem as it 

 were dead, the power of repeating for themselves the same opera- 

 tions. When once we understand it, however, as a general law, 

 that it is a property of organised structures to produce the same, 

 there is little difficulty in comprehending how they impart to the 

 elements they employ, properties so different from those which 

 they previously possessed. For we find in every case, that a 

 change of combination in these elements is attended with a change 

 in their properties. Thus an acid (such as oil of vitriol) and an 

 alkali (such as soda) have properties peculiar to themselves, and 

 in many respects contrary to those of each other ; but when they 

 are brought together, they unite into a new compound, which 

 possesses a form and properties differing from those of either of 

 its elements. Again, sulphur, nitre, and charcoal, when simply 

 mixed together in certain proportions, form a product, gun- 

 powder, which possesses properties very different from those of 

 either of its elements. Thus, then, we see that there is nothing 

 improbable in the supposition, which all analogy supports, that 

 the properties peculiar to organised structures depend upon the 

 peculiarity of their constitution ; and this peculiarity, which the 

 chemist and the mechanic alike fail to imitate, results, as we 

 have seen, from the general law, that organised structures can 

 only take their origin from beings already possessed of life. 



9. One more preliminary consideration must be adverted to, 



