108 NATURAL SCIENCE [August 1898 
question is, which can bring forward the greater number of correlated 
facts in support of these two deductions, respectively, 7.¢.,so that they 
may be supported by inductive evidence? Now gravity is claimed 
as acting on one petal, but it cannot account for the erect stamens 
and style in the dead-nettle, and all the rest of the features of the 
flower. My suggestion is that the irregularity seen in all the organs 
of the flower are brought about by one and the same cause,—the 
mechanical action of the insects which visit it. 
Assuming the deduction as a working hypothesis, I bring forward 
(1) abundant evidence to show that protoplasm responds to mechan- 
ical forces and builds up structures to meet the strains to which it 
is subjected ; (2) the ribs of the calyx and its form corresponds pre- 
cisely with the distribution of forces, as seen in Salvias. The form 
of the corolla is just what would result if it be supposed to be plastic 
and moulded to the form of an insect, as in Anhatoda. The stamens 
are erect or declinate, in correspondence with a flower having a 
landing-place on the corolla or not. The honey-gland is situated, 
and the ‘ guides’ directing to it, precisely in adaptation to the insect 
visitor. In fact, the entire flower is simply a vast accumulation of 
innumerable coincidences, all conspiring to one and the same end. 
It is this which constitutes inductive evidence: while all the correla- 
tions are based on the well-known properties of protoplasm, the 
accumulation of coincidences affords a probability of so high an 
order as to amount to a ‘moral conviction,’ and such—all logicians. 
admit—is equivalent to a ‘ demonstration.’ 
Similarly, I maintain by inductive evidence that Monocotyledons: 
have descended from aquatic Dicotyledons. 
These two lines of proof are amply sufficient, as scientific 
evidences, to establish the truth of any theory, and convert it into. 
a natural law. 
I think I have now said enough to show the utter incompetency 
of & priori assumptions to prove anything at all, of themselves. They 
are simply deductions, without verifications, and as such remain 
utterly valueless, and instead of advancing any branch of science, 
do but retard it, as long as they are accepted without verification. 
Their danger, however, is subjective not objective. A deduction 
or @ priori assumption is useful only as the first step. It must be 
verified. It is the fatal facility of guessing inherent in mere think- 
ing, irrespective of facts—to collect which is a laborious process, in 
which Darwin set so grand an example, and upon which evolution 
was based. This is the imperishable result of his labour, while the 
theory of Natural Selection, as having anything to do with the Origin 
of Species, was a quite subordinate matter, and has turned out to be: 
a broken reed to rely upon. GEORGE HENSLOW. 
Drayron Houssr, EALInG, W. 
