XLVI THE ROYAL SOCIETY OF CANADA 
each only half of that characteristic number, so that when the egg is 
fertilized one half of its nuclear material is of paternal and one-half 
of maternal origin. It is not therefore singular that most biologists 
attribute to this nuclear matter a predominant significance in the 
transmission to the offspring of hereditary characters. It is especially 
during the last decade that eager researches have been made into this 
aspect of cytology, with results which explain, in many cases, the de- 
termination of sex and, in conjunction with the observations of Mendel, 
the peculiar phenomenon of sex-limited inheritance. 
It is not singular that the study of Heredity should form at present 
one of the most burning questions of Biology. So recently has the 
jubilee of Darwin’s Origin of Species been celebrated that it is hardly 
necessary to point out how the doctrine of evolution has fertilized 
every branch of human knowledge since its general acceptance by the 
scientific world; but it may be well to remind you that to teach evolution 
at the beginning of the period we are considering was still regarded as 
dangerous. Organic evolution depends upon the two factors of heredity 
and variation, and although there is much which is obscure with regard 
to the intimate nature and causes of these phenomena, and although 
natural selection may not be the only determining cause of the origin 
of new forms and, indeed, has recently met with much adverse criticism, 
yet there is now no hesitation as to the acceptance of the doctrine of 
evolution itself. 
But Heredity has not only been attacked from the cytological 
aspect. A new branch of experimental Biology, stimulated by the 
redi$covery of the researches of the Abbé Mendel has been developed, 
dealing with the laws of hybridization and the crossing of varieties 
and races of plants and animals, not in the haphazard way of the cul- 
tivator and breeder, but by means of rigid analysis, searching out the laws 
of the transmission of hereditary characters. Already notable results 
have been arrived at in combining desirable qualities in cereals and 
in foreseeing the nature of the results of such crossings. 
A third method of approaching the problem of heredity—the 
statistical method, chiefly elaborated in relation to Man by the late 
Sir Francis Galton, and more recently by Professor Karl Pearson— 
has lately arrested the attention of the public in consequence of the 
disposition of Galton’s fortune. You are aware that he bequeathed a 
large sum (£45,000) for the creation of a Chair and the establishment 
of a Laboratory of Eugenics in the University of London. His re- 
searches had convinced him that the characters transmitted hereditarily 
are of greater importance in determining the constitution and character 
than the environment (as he expressed it, “Nature is stronger than 
nurture’), and led him to the conclusion that a nation, to avoid de- 
cadence, must turn its attention to the quality of its future generations. 
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