177 
production of the mean of the whole. Under these condi- 
tions heredity tends to uniformity of type if the numbers 
ra 
E then a new B AER N isolation, comes into 
play, and an evolution or evolutions of type appear as a re- 
sult. The diversities of these results will depend p the 
p 
separated part is comparatively small, the divergent a 
would be proportionately marked and appear at an earlie 
date. 
ully appreciate the effects of isolation, considerable em- 
ee is laid on the species of isolation as distinguished from 
the form of isolation, the former being much more importan 
as an evolutionary factor. In other words, is the isolation 
it is a breeding of like with in the indiscriminate it is 
an teet — di members at a simply 
isolation ; : simply into numeri ally two equal parts it will 
e a case indiscriminate isolation. Unfortunately, dif- 
ferent names have been given to s two kinds of ee 
r in- 
y 
of isolation may be at work ; thus, if a group of intergeneran 
be segregated into five groups, a, 5, c, d, e, then before tne 
M 
