OF ORGANIZED STRUCTURES IN GENERAL. 19 



nesian Archipelago, or of which the debris seem to have constituted 

 many of the calcareous rocks of ancient formation. But in these cases, 

 the increase is produced by the multiplication of similar parts, which, 

 when once completely evolved, have but little dependence upon one ano- 

 ther, and might be almost considered as distinct individuals. Thus, 

 each bud of a tree, if placed under favourable circumstances, can main- 

 tain its life by itself, and can perform all the actions proper to~tfre 

 species. Each polype of the coral mass, in like manner, at first pro- 

 duced by a process of budding from the original stock, comes in time to 

 be completely independent of it, and of those with which it is associated. 

 And in the sea-weed, each portion of the frond is an almost precise repe- 

 tition of every other, and grows for and by itself ; neither receiving 

 from nor communicating to, any other part, the materials of its organic 

 structure. Thus among Plants and the lower Animals, we find an 

 indefiniteness in point of size, depending upon the tendency to multiplica- 

 tion of similar parts, which has been designated as vegetative repetition. 



4. It is, however, in the internal arrangement or aggregation of the 

 particles, respectively composing Organized structures and Inorganic 

 masses, that we find the difference between the two most strongly 

 marked. Every particle of a Mineral body (in which there has not 

 been a mixture of ingredients) exhibits the same properties as those 

 possessed by the whole ; so that the chemist, in experimenting with any 

 substance, cares not, except as a matter of convenience merely, whether 

 a grain or a ton be the subject of his researches. The minutest atom of 

 carbonate of lime, for instance, has all the properties of a crystal of this 

 substance, were it as large as a mountain. Hence we are to regard a 

 mineral body as made up of an indefinite number of constituent particles, 

 similar to it and to each other in properties, and having no further re- 

 lation among themselves than that which they derive from their juxta- 

 position. Each particle, then, may be considered as possessing a sepa- 

 rate individuality ; since we can predicate of its properties all that can 

 be said of the largest mass. The Organized structure, on the other 

 hand, receives its designation from being made up of a number of dis- 

 tinct parts or organs, each of which has a texture or consistence peculiar 

 to itself; and it derives its character from the whole of these collectively. 

 Every one of these, as we shall hereafter see, is the instrument of a 

 certain action or function, which it performs under certain conditions ; 

 and the concurrence of all these actions is required for the maintenance 

 of the structure in its normal or regular state, and for the prevention 

 or the reparation of those changes, which chemical and physical forces 

 would otherwise speedily produce in it, from causes hereafter to be ex- 

 plained. Hence ther.e is a relation of mutual dependence among the 

 parts of an Organized structure ; which is quite distinct from that of 

 mere proximity. Thus, the perfect plant, which has roots, stem, leaves, 

 and flowers, is an example of an organized structure, in which the rela- 

 tion of the different parts to the integrity of the whole is sufficiently 

 obvious ; since, when entirely deprived of either set of these organs, the 

 race must perish, unless the plant have within itself the power of re- 

 placing them. 



5. It is not only in Zoophytes and other aggregate Animals, that we 



