44 FOOT-NOTES TO EVOLUTION. 
century has been largely wasted. Which of the forms we 
study are species, and therefore represent separate acts 
of the Creator, and which are mere varieties, chance 
products of varying surroundings, and 
therefore to be despised and ignored? 
Scarcely ever did two earnest students 
of any group reach an agreement as to this question, for 
agreement is only possible when material is lacking. A 
single additional specimen often unsettles every conclu- 
sion, and the contents of all the museums are but the 
slightest fragment of the life of the globe. “We can 
only predicate and define species at all,” says Dr. Coues, 
“from the mere circumstance of missing links. Our 
species are twigs of a tree separated from the parent 
stem. We name and arrange them arbitrarily in default 
of means of reconstructing the whole tree in accordance 
with Nature’s ramifications.” Among Dareste’s eels we 
may have one species, or four, or forty, as our collection 
may be deficient in connecting forms, or as we may 
choose to magnify or disregard slight differences. There 
are just as many kinds of eels as there are races of men 
or of dogs. Future naturalists will again describe those 
eels; but they will know them for what they are—the 
varying descendants of some one degenerated type of 
fishes, crawling in the weeds and ooze of many seas 
and rivers, and thus variously modified by their sur- 
roundings. 
Meanwhile the old notion of a species has passed 
away forever. We can no more return to it than as- 
tronomers can return to the Ptolemaic 
notion of the solar system. The same 
lesson comes up from every hand. It is 
the common experience of all students 
of species. I do not know of a single naturalist in the 
world who has made a thoughtful study of the relations 
The reality of 
species, 
The old idea of 
species has 
passed away. 
