52i 
of directions (even within the limits of a single species) that they 
may practically be regarded as ‘ omniferous.’ The Duke of Argyll, 
therefore, is dialectically in the wrong - , when he challenges Darwinists 
to prove that initial variations are indeterminate. The burden of 
proof lies with him to show that they are determinate. For the 
Darwinist can point to the results of ‘artificial selection’ unques 
tionably to demonstrate that, in our domesticated plants and animals, 
variation is so far omniferous as to lend itself to all the morpho 
logical changes in divergent lines which have been produced by the 
continuous, or cumulative, selection of the horticulturalist and the 
breeder. Why, then, are we to suppose that, in the case of wild 
species, the principles of variation are different ? If they are so, it 
remains with anti-Darwinians to prove the fact.”—{Contemporary 
Review, vol. liii., p. 830.) 
But it would seem as if the advance of scientific in 
vestigation had provided the opponent of Natural Selec 
tion with, the very instance which Mr. Romanes challenged 
him to find. And it is to be noted that it is Mr. Romanes 
himself who, with a fine generosity and loyalty to truth, 
states the case even more strongly than the Duke of 
Argyll had done. The particular case is the evolution of 
the electric organ in certain fish, of which Mr. Romanes 
says:— 
“ Electric organs are known to occur in several widely different 
kinds of fish ; wherever these organs do occur, they perform the 
function of electric batteries, in storing and discharging electricity 
in the form of more or less powerful shocks. Here, then, we have a 
function which is of obvious use to the fish for purposes both of 
offence and defence. ... In the particular case of the skate, 
. . . although its structure is throughout as complex and perfect 
as that of the electric organ in Gyvinotus or Torpedo, its smaller size 
does not admit of its generating a sufficient amount of electricity to 
yield a discharge that can be felt by the hand.” Nevertheless, there 
is a discharge ; but “ such weak discharges as the skate is able to 
deliver must be wholly imperceptible alike to prey and to enemies. 
Yet for the delivery of such discharges there is provided an organ 
of such high peculiarity and huge complexity that, regarded as a 
piece of living mechanism, it deserves to rank as at once the most 
extremely specialised and the most highly elaborated structure in the 
whole animal kingdom. . . . Therefore it appears impossible to 
suggest how this astonishing structure—much more astonishing, in 
my opinion, than the human eye or the human hand—can ever have