THROUGH CUMULATIVE SEGREGATION. 
219 
As a convenient method of illustration, let us consider the 
different results that will be gained according as we subject the 
same ten pairs of wild rock- pigeons to one or the other of the 
following methods of treatment. 
In the first experiment let the treatment be as follows : — Let 
ten aviaries be prepared ; and in each aviary put one male with 
the female that most nearly resembles it. When the young of 
each aviary arrive at maturity, let them be inspected, and if any 
individual resembles the inmates of one of the other aviaries 
more than the inmates of the aviary in which it was produced, 
let it be placed with those it most closely resembles. If any 
unusual variation arises, let it be placed in a new aviary, and let 
the one of the other sex that most closely resembles it in that 
respect be placed with it. When the crowding in any aviary 
becomes injurious to the health of the birds let the numbers be 
indiscriminately reduced. Let this process be continued many 
generations, the inmates in all the aviaries being fed on the same 
food, and in every respect treated alike, and what will be the 
result ? 
No experienced breeder will hesitate in assuring us that under 
such treatment a multitude of varieties will be formed, many of 
which will be very widely divergent from the original wild stock. 
In other words, Cumulative Segregation will produce accumulated 
divergence, though there is no Selection in the sense in which 
Natural Selection is Selection. 
Again, let us take the same ten pairs, and putting them into 
one large aviary, let them, breed freely together without any 
Segregative influence coming in to affect the result ; and who 
does not know that the type would remain essentially one 
though a considerable range of individual variation might arise. 
That is, without Segregation no divergence of type ivill arise. 
The Natural Law or Cumulative Segregation. 
I shall now show that there is in nature a law of Cumulative 
Segregation. There are large classes of activities in the organism 
and in the environment that conspire to produce Segregate 
Breeding ; and to produce it in such a way that, in a vast mul- 
titude of cases, it becomes a permanent fact, which no cause 
that w T e are acquainted with can ever obliterate. Moreover, 
when one form of Segregation has become fully established, we 
