179 
succession and modification from wing, properly so called. I 
cannot trace tlie steps, and think there are strong reasons 
for believing there are none. The whole of the bird's bones 
are solid ; not hollow, for the sake of lightness, as in flight- 
birds. The sternum is a mere buckler, without the keel of 
the flying tribes ; neither has it any abdominal air-cells. The 
whole frame is utterly opposed to flight. It is that of a purely 
land animal. If the ancestors of this terrestrially-made bird 
ever flew, I could understand how, from long disuse, it might 
have lost its flight-powers; and how, the same conditions 
always present, they might perhaps gradually wither quite 
away. But why should that part of the osseous structure, 
unconnected with the organs of flight, be so generically 
changed ? The entire bulk is unadapted for flying, not the 
rudimentary wing alone. If it be argued by the continuitist 
that the frame has changed for the descensive reason that 
abolished the wing, he is making the frame in its totality an 
engine of flight, which is untrue of any bird. Again, do the 
warmest advocates of continuity pretend that it adds to, as well 
as takes from, — at least where they are making use of the argu- 
ment of rudimentary organs ? In the present example, we have 
this gradually “ worn-down " wing furnished at its extremity 
with a hook. How can we account for the phenomenon of 
addition ? I see but one principle which can do that ; the 
ancestral Apterix possessed the same instrument, and there- 
fore never had a true wing. 
None of these citations appear to be very well calculated 
to sustain the system of continuity. 
In this class of thinkers, a good deal of argument will be 
found bestowed on the confusion of primary and secondary 
powers. “ If," says Mr. Grove, “ we now assign to the heat 
of the sun an action enabling vegetables to live by assimilating 
gases and amorphous earths into growing structures, why 
should such effects not have taken place in earlier periods of 
the world's history, when the sun shone as now, and when the 
same materials existed for his rays to fall upon ? " His rays 
are called upon to aid in keeping existing organisms alive ; 
which is all he can be proved to do now, and which he always 
did since vegetable was. Before then, there were the 
“materials," but nothing else. The sun is one of the aids 
in reproduction ; how can we thence argue that he brought 
the first vegetation into life ? There are no more grounds 
for this, than to consider original introduction and subsequent 
reproduction the same act, or effected by the same means. 
The difference appears to me as obvious as that between the 
seed and the plant ; the plant springs from the seed, which is 
