EVOLUTION OF THE CHEMICAL ELEMENTS. 527 



closest embryological study can reveal their composite nature. On the 

 other hand, corals as well as many protists, such as the Labyrinthulece, 

 coexist with so small a degree of integration that the parts are con- 

 sidered as distinct individuals, although clearly dependent on one 

 another. 



The vegetable kingdom illustrates still more clearly the manner in 

 which the aggregates are compounded. We have plants, like Cau- 

 lerpa, which, while the form would lead us to expect a considerable 

 degree of organization, consist in reality of a simple aggregation of 

 homoo-eneous cells. In higher plants, the leaf forms a new order of 

 organization, and constitutes the morphological individual or unit. In 

 trees, the process of compounding has gone so far that, considered as 

 individuals, they may reach the hundredth degree. 



If we contemplate the mineral kingdom, we are again shown the 

 same truth. The various recognized minerals are not generally found 

 to be composed directly of the simple chemical compounds into which 

 they may be resolved, but consist of compounds of different orders 

 into which the simpler compounds enter as units of composition. 

 Thus feldspar contains silica, alumina, peroxide of iron, lime, soda, 

 potash, magnesia, water, etc., as units of composition, none of which 

 is supposed to exist in the mineral in any simpler state, and all of 

 which are already more or less complex chemical compounds. More- 

 over, two or more of these minerals thus formed often again combine 

 as new units to form others of still higher organization. 



When we consider the facts which chemistry furnishes, we see the 

 same law still operating in great simplicity. In many of the binary, 

 ternary, and higher compounds, theory requires us to assume that the 

 substances entering into them do so in their integral state, and are not 

 first decomposed into their primary elements and then reorganized 

 into the new compound. The hydrated oxide of potassium, for exam- 

 ple, is not written KH^O^, but \^0,\lfi, in which both the immediate 

 constituents are regarded as maintaining their composite state and 

 entering bodily into the new compound. The entire series of " com- 

 pound radicles " requires the same supposition and illustrates the same 

 general principle. Cyanogen (CN), ammonium (NHJ, methyl (CHJ, 

 ethyl (CjHJ, and the rest are now held to constitute integral units in 

 the formation of the hydrides, alcohols, and acids. 



So far, then, as induction can be depended upon, we find that it is 

 a universal law of the aggregation of matter that each new aggregate 

 may become a unit for the formation of aggregates of higher orders. 

 Does this law cease with the so-called chemical elements, or are these 

 themselves the products of molecular aggregation ? 



Without discussing the old and apparently in solvable problem of 

 the divisibility of matter, it may be remarked that while the known 

 facts of science are entirely satisfied with the hypothesis of an ulti- 

 mate, finite unit of matter, of which all perceptible objects are but 



