350 
LOCK : STUDIES IN PLANT BREEDING 
in number of the “ Anlagen ” takes place in certain cases in 
a perfectly definite and simple fashion. 
Reference has been made above to the four schemes of 
inheritance enunciated by Correns. Tschermak (60) has given 
an account of 64 such schemes in support of the objective 
reality of several of which he finds evidence in crosses 
between races of cereals. The distinctions between the 
greater number of these systems are concerned with 
differences in the vegetative development of the zygotic 
organism. Very few cases in which Mendelian segregation 
in the gametes does not take place have hitherto been worked 
out completely, although such undoubtedly occur. 
Doubt has been expressed in certain quarters as to the 
sufficiency of the evidence of any case of Mendelian segre¬ 
gation so far published. But it appears to me to be impossible 
for any one, who has made definite experiments with certain 
characters in peas or in Indian corn, to doubt the validity of 
Mendel’s explanation of the phenomena which he observed. 
Finally I desire to express my thanks to those who have 
given me assistance during the course of the work herein 
partly described. I am particularly indebted to Mr. W. 
Bateson for a constant stream of information and advice most 
generously given. I am also greatly indebted to the staff of 
the Peradeniya institution, especially to the Director, Mr. J. 
C. Willis, on whose advice and by whose permission the 
work was undertaken ; to Mr. Herbert Wright, who has aided 
me both personally and with the resources of the Experiment 
Station ; and to Mr. H. F. Macmillan. I would also gratefully 
acknowledge the kindness of Mr. H. Webber of the U.S.A. 
Department of Agriculture, of the Director of the Calcutta 
Botanic Gardens, and of Mr. I. H. Burkill, from all of whom I 
have received supplies of seeds which have been made use 
of in the experiments. 
SUMMARY . 
In 1866 Gregor Mendel showed that, in the case of certain 
pairs of alternative characters in peas, the said characters, or 
