4 
all of us who love natural science, is the question — how far the 
theories of development and evolution, commonly called Darwin- 
ism, are to be considered as having been established, and are to be 
received as a solution of the difficult problem of the origin of 
species, and as a step towards that of the still more obscure problem 
of the origin of life ; and while we look with the utmost regard on 
that masterly course of observation and reasoning which has taught 
us so clearly how varieties are formed within species, as, for instance, 
among domesticated animals, we some of us, perhaps, hardly see 
our way to accept development as the origin of species themselves, 
or evolution as the means by which all the forms we meet with 
have been produced from one source, or from a few original types. 
In the first place, we are puzzled to know where varieties end 
and species begin ; and those who should be best informed on this 
point, seem in many cases not at all more certain than we are as to 
their limits ; the views of the same authority differ widely from 
time to time, and different authorities hold diametrically opposite 
views. Let us take, for example, the group of British Batrachian 
Ranunculi. In 1851, Professor Babington described them as seven 
species, and three varieties; but in 1874 he divides them into 
thirteen species and one variety ; while Dr. Hooker, in 1870, gives 
but three species, describing all other forms as sub-species or 
varieties, and says, ‘ ‘ the species of this section are considered by 
some authors as forms of one or two, by others as twenty to thirty.” 
Nor have I chosen at all an extreme example ; some of the other 
“ critical genera ” of British plants would show a still wider dis- 
crepancy between the views of our leading botanists, forcing us to 
the conclusion that our conception of species is too narrow : that 
the variation of form, colour, and even of structure, that may exist 
among varieties within the limits of a species, is very much greater 
than we are apt to admit ; and that before we are at all prepared 
to consider “ species ” as the unit of development, we shall have to 
get rid of a good many notions founded on taxonomic arrangement 
and in the words of one of our greatest English botanists, “ the 
time will ere long arrive when what are now called genera, or sub- 
genera, will alone be considered specios.” 
