Recent Advances in the Study of Heredity, i 79 
phenomenon itself stands in such sharp contrast to what our pre¬ 
conceived ideas about the relation between successive generations 
would lead us to expect, in order to support my thesis that 
the new ideas introduced by the study of hybridization are in reality 
of two distinct kinds : (i.) those new conceptions introduced by 
both Mendel and Weismann and (ii.) those ideas which are 
exclusively due to Mendel and his followers. 
But I also wish to lay stress on the experiment which I have 
recorded for another reason. Mr. Lock adds a postscript to his 
paper on the “ Present State of Knowledge of Heredity in Pisurn ” 
to which I have already referred, which involves a question relating 
to the interpretation of natural phenomena which is, in my opinion, 
of first-rate importance. The postscript was as follows “ In 
Nature of August 22nd, 1907 there appears an anonymous statement 
to the effect that no one has repeated Mendel’s experiments with 
the deliberate intention of testing the Mendelian interpretation of 
the results. The curiosity naturally excited by this statement as to 
what other object—in the opinion of the writer of the review— 
could have been in the minds of all those who have laboriously 
continued Mendel’s inquiries, is only partly allayed by the explanation 
of the same writer in Nature of September 12th. Here we find 
that what was meant was that crucial experiments had not been 
carried out by sceptical 1 observers on certain lines which are indicated. 
In addition to numerous crosses between heterozygote and 
recessive carried out with sufficiently conclusive results in the case of 
peas, the present writer has actually carried out on a considerable 
scale an experiment with Zea Mays on lines closely similar to those 
indicated in Nature of September 12th, 1907. An account of these 
experiments appeared in Nature of October 20th, 1904, and a full 
description of them has since been published. 2 
I feel bound to add that since the successful issue of these 
experiments I am no longer sceptical as to the accuracy of Mendel's 
experiments or of his deductions from them. And if, as it would 
appear, Nature's reviewer demands confirmation by an observer who 
shall remain sceptical after the event, I am afraid his doubts are 
unlikely to be done away with. For I know of no sane person who 
has carried out a reasonable number of experiments on Mendelian 
lines and still retains the required mental attitude.” 
1 Mr. Lock’s italics. 
2 R. H. Lock. “ Studies in Plant Breeding in the Tropics, III. 
Experiments with Maize.” Ann. Roy. Bot. Gardens 
Peradeniya, III., ii., p. 95, 1906. 
