582 The Evolution of Matter 
changes are interposed between two radio-active transformations 
which can be followed, show that spontaneous transmutation is 
possible without measureable radio-activity. And, indeed, any theory 
of disintegration, such as Thomson’s corpuscular hypothesis, would 
suggest that atomic rearrangements are of much more general occur- 
rence than would be apparent to one who could observe them only 
by the effect of the projectiles, which, in special cases, owing to some 
peculiarity of atomic configuration, happened to be shot out with 
the enormous velocity needed to ionize the surrounding gas. No 
evidence for such ray-less changes in ordinary elements is yet known, 
perhaps none may ever be obtained ; but the possibility should not 
be forgotten. 
In the strict sense of the word, the process of atomic disintegra- 
tion revealed to us by the new science of radio-activity can hardly 
be called evolution. In each case radio-active change involves the 
breaking up of a heavier, more complex atom into lighter and 
simpler fragments. Are we to regard this process as characteristic 
of the tendencies in accord with which the universe has reached its 
present state, and is passing to its unknown future? Or have we 
chanced upon an eddy in a backwater, opposed to the main stream of 
advance? In the chaos from which the present universe developed, 
was matter composed of large highly complex atoms, which have 
formed the simpler elements by radio-active or ray-less disintegra- 
tion? Or did the primaeval substance consist of isolated electrons, 
which have slowly come together to form the elements, and yet have 
left here and there an anomaly such as that illustrated by the 
unstable family of uranium and radium, or by some such course are 
returning to their state of primaeval simplicity? 
