304 
LOCK : STUDIES IN PLANT BREEDING 
Darwin’s “ Origin of Species ” was published in 1859, his 
“Variation in Animals and Plants in 1868.” 
Mendel’s paper on peas was read in 1865, and that on 
Hieracium in 1869. In 1865 also appeared Wichnra’s account 
of willow hybrids (78), in which the strictly intermediate 
form of most of the hybrids examined was strongly em¬ 
phasized. 
In 1881 Focke in his “ Die Pflanzen-Mischlinge ” gave an 
able account of the progress of the knowledge of hybrids up 
to that date. This work contains also a useful historical 
summary. Mendel’s work is briefly referred to, but its full 
importance is not recognized. 
Naegeli s “ Mechanisch - physiologische Theorie dor 
Abstammungslehre ” was published in 1884, and Weismann’s 
well-known essays upon Heredity were appearing about the 
In 1889 Galton in his “ Natural Inheritance ” gave a very 
clear account of his application of statistics to the problems 
of heredity. From various human characters he deduced 
the value ^ for “ filial regression.” Although most of his 
own observations were directed to the elucidation of the 
laws of “normal variability” Galton recognized the probable 
importance of discontinuous variations in evolution. 
Macfarlane in 1892 (48) showed that the minute structure 
of plant hybrids agrees with their external appearance in 
showing characters usually intermediate between those of 
the parental forum. 
Millardet’s remarkable account of “ False hybrids ” ap¬ 
peared m 1894. In the same year Bateson’s work “ Materials 
or the Study of Variation ” was published. The author 
criticized a number of biological conceptions then current, 
pd showed that the whole tendency of the material accumu- 
ated was to indicate the importance of discontinuous 
^ddefi 8- ^ ^ ° rigin ° f 8 P ecieB - Without attempting a 
Bateson indicated the difference between the tJo kinds of 
