362 
PEOFESSOR K. PEARSON AND OTHERS ON 
On the other hand, great diversity in the variability of different sjDecies. I do not 
wish to be dogmatic on this point, however, but I would definitely assert that so far 
no relationship between variability and homotyposis is discoverable. Further, it does 
not seem to me that looking down the order of variability we can assert that our table 
in any way corresponds to the order of evolutionary descent. It does not seem to 
me that the species towards the top of it are the more primitive and those towards 
the bottom the more complex. Indeed two series of the same species may stand at 
very different points in the table. I am accordingly forced to the conclusion that my 
taljle gives no support whatever to the view that variability in the vegetable kingdom 
is greatest for the more primitive and simpler organisms. Nor, again examining 
Table XXXII., can we conclude that homotyposis is least intense for such organisms, 
for the second half of our table cannot be said to contain more of such organisms than 
the first. Shortly, I see no relation l^etween the position of an organism in the 
evolutionary descent and the intensity of either its variability or its homotyposis. 
Hence it follows that, if homotyposis be the source of heredity, the intensity of the 
latter cannot be related to either variability or position in evolutionary descent. 
Mr. Adam Sedgwick may be right in his view"^ that in the early stages of evolution 
variability is large and inheritance small, and that with development this relation is 
changed, variability decreasing with an increasing intensity of heredity. My 
statistics only cover a small jiortion of one kingdom. But so far as I am aware 
they represent the only material so far 2 )uljlished on vliich a definite judgment can be 
founded—where by definite judgment, I mean one based on quantitative facts, and 
not drawn from a general estimate of nature R’hich makes no statement whatever 
of the intensity of either variability or heredity for any single character in any one 
species of living things. 
The data I have given seem entirely opposed to Mr. Sedgwick’s view, but I very 
fully realise that they are far from exhaustive. They indicate, however, vliat 
I hold to be the only valid method of approaching any problem in variation or 
heredity, fir., laborious statistical collection of actual facts. My statistics may be 
insufficient, I would heartily welcome additions to them ; or they may be dealt with 
fallaciously. Here is the material; let others add to and, if need be, modify the 
conclusions. Only let us follow the method so clearly indicated by Harwik himself 
in his ‘ Cross and Self-fertilisation of Plants ; ’ let us cease to propound hypotheses 
illustrating them liy isolated fimts or vague generalities ; there are innumerable 
species at hand in Nature ready for us to measure and count. Sine ninnero nihil 
demonstrandum est, should now-a-days l)e the motto of every naturalist who desires 
to propound novel hypotheses with regard to variation or heredity. It is equally valid 
for those who merely seek either to establish more firml}^ or to modify the old. 
(2G.) I would sum up the results of this memoir in the following conclusions ; 
Presideiitiul Address to Section 1) of the British Association, 1890. 
