DOES HYBRIDISATION INCREASE FLUCTUATING VARIABILITY ? 113 
school. We know few such correlation coefficients for cases of self- 
fertilisation or vegetative reproduction, but the coefficients that have 
- been determined exhibit one common characteristic—the coefficients of 
the offspring with the higher ancestry are always less than the correlation 
with the parent. If Professor Johannsen’s view, as I understand it, were 
true, and the germinal type were absolutely and rigidly fixed, then in 
the mass of the population, the correlation between the offspring and the 
grandparent would be identical with that between the offspring and the 
parent. We have not many data, as I have said, but such as exist seem 
against Professor Johannsen’s view, and accordingly I feel inclined to 
hold my judgment in suspense until the question has been further 
studied. 
The President: We must expect the answer to come from later 
generations. Pending further tests we are bound to suspend our 
judgment. 
Mr. C. C. Hurst, Hinckley, England: In view of the discussion I 
might remark that I have also been carrying out some experiments of the 
same nature as those Professor Johannsen has been engaged upon. I 
have chosen the Dutch rabbit, which is very fluctuating, and I might say 
that up to now the results are of a purely negative nature. I hope to be 
able to report shortly, but at present the continuous variations are 
hereditable. Professor Johannsen also stated that Mendel’s experiments 
did not touch the question of continuous variation. That is true in a 
sense; but I should like to point out that before Mendel’s experiments 
were begun, our general ideas of variation were that continuity was the 
rule and discontinuity almost the exception. I think the solitary person 
who recognised the great value of discontinuity was our worthy President, 
Mr. Bateson, long before Mendel was known, and when the rest of us were 
sticking to Darwin’s continuity. When we made an experiment with 
sweet peas, before Mendel was known, and we found in the F, generation 
purples, reds, and whites, and all the different gradations of colour, we 
should at first sight have said that that was the effect of variation. Now 
we know, from the experiments of Bateson and Miss Saunders, that dis- 
continuity is the rule with sweet peas. Therefore I think it is only fair 
to point out that the supposed continuous variations are really dis- 
continuous. We shall find that almost all the hereditable characters are 
discontinuous in nature, and that the continuous variation is merely 
somatic and altogether apart from heredity. 
