1882.J The Law of Evolution : is it General ? 7 
nation and the sudden and complete change which ensues 
when elementary bodies unite together to form some com- 
pound ; but it may, even in this respeCt, be submitted that 
what in the simpler inorganic bodies appears so discon- 
tinuous is greatly modified in the higher organic compounds. 
In such bodies as water, ammonia, the anhydrides, the me- 
tallic oxides, &c., we find two elements only present, a single 
atom of one of these being united to one, two, three, or 
perhaps four of the other, forming distinct stages between 
which there is nothing intermediate. But in organic com- 
pounds the combining weight of each element has often to 
be multiplied by some very high number, and thus the series 
becomes continuous, the law of definite proportions notwith- 
standing. We have said above that the lower inorganic 
kind of chemical compounds have no embryonic intermediate 
state. But as the higher organic compounds appear to be 
formed not by the union of distinct and simple atoms, but 
of groups of atoms which are in themselves compound, it 
may be asked whether these proximate constituents do not 
in some degree stand in the stead of an embryonic state ? 
We have referred to the absence of an intermediate stage 
in such cases as the formation of water ; but the study of 
living bodies supplies us with a transformation no less sud- 
den. Matter is either living or lifeless ; there is no inter- 
mediate third stage. A particle of lifeless inorganic matter 
brought into contact, under certain circumstances, with the 
organised body flashes into life. The “ merorganic ” stage 
of certain chemists and physiologists of the second quarter 
of the present century is no longer recognisable. Com- 
paring, then, the two pictures, the table of the elements, 
and the general features of chemical phenomena, on the one 
hand, and on the other the ranks of the organic kingdoms 
and the laws of vital phenomena, we see no such decided 
distinction as would forbid us from pronouncing the former 
as situate altogether outside the scope of the law of Evolu- 
tion. And if we pass from the simple elements to their 
compounds actually existing upon the earth, we find that 
the analogy becomes closer, — that we may even trace some 
of the workings of the principle of Natural Selection. This 
will appear as follows : — The elements have, we believe, 
varying tendencies to combine among themselves, just as 
organisms have inborn tendencies to modification in certain 
directions. These tendencies are, however, exerted under 
varying conditions of temperature, pressure, mutual propor- 
tion, access or non-access of air and moisture, and presence 
or absence in each case of substances capable of interfering 
