42 
DARWINISM 
CHAP. 
have been carefully described, so that we possess a consider¬ 
able mass of information on the subject. Utilising this in¬ 
formation we Avill now endeavour to give some idea of the 
nature and extent of variation in the species of animals and 
plants. 
It is very commonly objected that the widespread and 
constant variability which is admitted to be a characteristic of 
domesticated animals and cultivated plants is largely due to 
the unnatural conditions of their existence, and that we have 
no proof of any corresponding amount of variation occurring 
in a state of nature. Wild animals and plants, it is said, are 
usually stable, and when variations occur these are alleged to 
be small in amount and to affect superficial characters only ; 
or if larger and more important, to occur so rarely as not to 
afford any aid in the supposed formation of new species. 
This objection, as will be shown, is utterly unfounded ; 
but as it is one which goes to the very root of the problem, it 
is necessary to enter at some length into the various proofs of 
variation in a state of nature. This is the more necessary 
because the materials collected by Mr. Darwin bearing on 
this question have never been published, and comparatively 
few of them have been cited in The Origin of Species ; while a 
considerable body of facts has been made known since the 
publication of the last edition of that work. 
Variability of the Lower Animals. 
Among the lowest and most ancient marine organisms are 
the Foraminifera, little masses of living jelly, apparently 
structureless, but which secrete beautiful shelly coverings, 
often perfectly symmetrical, as varied in form as those of the 
mollusca and far more complicated. These have been studied 
with great care by many eminent naturalists, and the late Dr. 
W. B. Carpenter in his great work—the Introduction to the 
Study of the Foraminifera— thus refers to their variability : 
“ There is not a single species of plant or animal of which the 
range of variation has been studied by the collocation and 
comparison of so large a number of specimens as have passed 
under the review of Messrs. Williamson, Parker, Rupert 
Jones, and myself in our studies of the types of this group 
and he states as the result of this extensive comparison of 
