IO 
A. D. Darbishire. 
manner throughout the animal and vegetable kingdoms. Indeed 
from the foregoing study of sex-inheritance, apart from the latter 
considerations, we should not expect males and females to be 
homologous throughout the whole organic world. Hence it is 
possible that the three Mendelian interpretations just mentioned 
may all be correct for some organisms; and, further, it is possible 
that sex may in some cases he found to be correctly described by 
assuming yet other gametic constitutions for male and female. 
LECTURE VIII. 
Theory of Ancestral Contributions in Heredity. 
I N my second lecture I dealt with an experimental test of the 
truth of the theory of heredity which I described as the theory 
of ancestral contributions. Professor Pearson, in a paper entitled 
“ The Theory of Ancestral Contributions,” published in the Pro¬ 
ceedings of the Royal Society (B), Vol. 81, 199, p. 219, made the 
following criticism of these results. 1 
“ Under the above title a paper has recently appeared by Mr. 
A. D. Darbishire.giving further experimental evidence with 
regard to the inheritance of certain characters in Peas. The paper 
is an interesting one, but the method is not, I venture to think, 
capable of answering the problems the author set himself. It has 
been supposed by some Mendelians that the theory of inheritance 
summed up in the * law of ancestral heredity ’ was in some way 
invalidated by investigations such as Mr. Darbishire’s, and that 
opinion consciously or unconsciously seems to be expressed in the 
paper just referred to.” 
Professor Pearson was perfectly justified, it seems to me, in 
detecting an expression of this opinion in this paper as it stands ; 
but as I do not hold it, I wish to explain how the misapprehension 
1 Proc. Roy. Soc., Vol. 81, B, p. 61, et. secj. 
