Galileo’s detection of Venus’ phases with his telescope gave 
the Ptolemaic system its coup de grace. Foucalt’s pendulum 
made visible the earth’s rotation. Torricelli’s experiment of 
balancing thirty-two feet of water against thirty inches of mer¬ 
cury ends “Nature abhors a vacuum.” Newton’s falling apple 
led to his discovery of the law of gravitation and changed the 
world of science. The Dechmann Laws of Determination of the 
Sex at Will and of the Cross-Transmission of Characteristics 
stand as a first formulation of a biological principle the eugenic 
importance of which transcends all computation. Thousands 
saw the apple fall, yet only one interpreted its motion into a pro¬ 
found Law of Nature. As since time immemorial it had been 
observed that (with puzzling variations) sons partook of the 
characteristics of the mother, and daughters of the father, yet it 
remained for a twentieth-century inspiration to intepret the phe¬ 
nomena into profound law. 
In science every important statement must be verifiable. This 
it is that which distinguishes the fabric of modern science from 
all previous fabrics, for example, the S u m m a of Thomas 
Aquinas. Science is credible, not because the intellectual power 
of its builders surpasses that of the Alexandrian philosophers, 
of the mediaeval Schoolmen, but because of its method. Each 
of its great strides dates from some happy experiment or ob¬ 
servation. When in my poultry yards as far back as 1903, I saw 
all the male chicks of a mating of Polish male and Brahma 
females grow up like Brahmas, and saw that the females had 
topknots on their heads, I was sure that behind the phenomenon 
was nature laws. When it became common poultry-breeding 
practice to list in fancy stock catalogues “cockerel matings” and 
“pullet matings,” when stock breeding became general on a sim¬ 
ilar rule, then I felt that the phenomena displayed should be 
defined in a comprehensive, unquestionable law. As I paced my 
study I beheld the human race. I saw it going forward, breed¬ 
ing in ignorance. I saw tubercular male and tubercular female 
producing tubercular child. I saw scrofulous blood mated with 
scrofulous blood. I saw humanity’s matings all made by a blind 
chance and chaos and disintegration, destruction, ahead. No, 
not quite this! For it is true there is a certain instinctive phychic 
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