But the situation is very little better when we come to deal with plants
and animals of our modern world. Because, with the many thousands of
students of natural science all over the world, each anxious to get into
print as the discoverer of some new form, the systematists have a dead
weight of names on their hands that by a rational and enlightened
revision could doubtless be reduced to but a fraction of their present
disheartening array. For as the result of the extensive breeding
experiments now being carried on under the study of what is called
Mendelism (a term that will be explained in the next chapter), it has
been found that great numbers of the "species" of the systematists or
classificationists will not stand the physiological test of breeding,
that is, they are found to breed freely together according to the
Mendelian Law. As William Bateson remarks:

"We may even be certain that numbers of excellent species recognized by
entomologists or ornithologists, for example, would, if subjected to
breeding tests, be immediately proved to be _analytical varieties_,
differing from each other merely in the presence or absence of definite
factors."[19]

The following from David Starr Jordan, the leading American authority on
fishes, will serve to show how numerous have been the new names invented
in recent years, all tending further to confuse and complicate the
problem of what is a species:

"In our fresh-water fishes, each species on an average has been
described as _new_ from three to four times, on account of minor
variations, real or supposed. In Europe, where the fishes have been
studied longer and by more different men, upwards of six or eight