14 BIONOMIC LAWS. 
ordination between sex and sex, and between the sexual elements of 
the group, as will secure impregnation, and the production of both 
male and female elements must be sufficient to prevent extinction. 
2. The Transformation of Races. 
The survival of a race or species depends on its having sufficient 
adaptation to the environment to secure maintenance, on there being 
sufficient compatibility between the sexes to secure fertility, and on 
the production of male and female elements in sufficient abundance 
to secure fecundity; but the presence of these conditions does not 
insure the transformation of the race or species enjoying these condi- 
tions, nor does the extinction of races or species lacking in these con- 
ditions insure transformation in the surviving forms. As domestica- 
tion prevents or greatly impairs reproduction in the elephant, this 
species does not survive under domestication and therefore escapes 
the transformation necessary to produce a domestic race. For a 
similar reason, the complete extermination of the American bison 
would not produce a new race of bisons; and it could have influence 
in transforming an associated species of some other family only in 
case the absence of the bison should introduce a change in the relative 
degrees of maintenance, compatibility, or fecundity possessed by the 
different variations of the species, so that the most successful should 
be other than those that were most successful during the period of 
association with the bison. A little reflection will reveal the fact 
that when the change of relative degrees of maintenance or fecundity 
pertains to races or species which are entirely prevented from crossing 
the relative numbers in which these groups exist will be changed, but 
that this will not be a cause of change in the characteristics of the 
groups, even if some of them become extinct. This will be distinctly 
seen if we take a definite case. For example, during one year turkeys 
may attract the attention of a poulterer, and the next year peafowls 
may become his favorites; but the change in the relative importance 
given to either species transforms neither the one or the other. 
Again, he may have a pair of a species which he would gladly multi- 
ply, but through difficulty in getting them to mate his success may be 
very limited; or in the case of a second desirable species that pairs 
freely, diminished fecundity may interfere with their multiplication, 
while at the same time a third species of no great value, but not 
limited by these disabilities, multiplies freely and is raised in large 
numbers. The point to be observed is that in all these cases the 
difference in the degrees of propagation of these different species is 
not a cause of transformation in the characteristics of the species. 
