276 REV. PROF. A. CALDECOTT, D.LITT., D.D., ON 
guidance of her processes has been placed at man’s disposal. The 
keen sagacity of a Cambridge biologist in a happy moment 
discerned the far-reaching significance of the forgotten labours 
of an Austrian abbot, and has lifted Mendelism to the front 
rank of biological interest to-day. 
This is not the place for attempting a sketch of the Mendelian 
theory as I understand it. I can only say that what seem to 
me to be its salient features are (i) the ascertaining that there 
are in organisms, in plants especially, certain qualities so 
defined and so regular as to be called “fixed” or “ unit- 
characters,” occurring either singly or in combinations; and 
(ii) the persistence of these by hereditary transmission, in spite 
of apparent disappearances or obscurations. 
The importance of this knowledge is that when man has 
ascertained the presence of such fixed characters he can step in 
and can eliminate or foster them according to his own desires 
and purposes. His function as selector is enlarged by this 
knowledge, for he can learn what characters natural process has 
brought to fixity and can be depended upon to transmit from 
generation to generation. And more, he can manipulate the 
organic processes, so as to bring together combinations of such 
unit-characters, over and above those which Nature herself had, 
so far, produced. And these can be varieties not of a fleeting 
and precarious kind, but of a relatively high degree of stability. 
Man’s range of control is enlarged from such violent changes as 
the suppression of darnel in favour of wheat, of substituting 
wolves by sheep. The empirical methods of guiding Nature 
hitherto used by breeders of stock and cultivators of plants are 
now placed on a scientific basis because we have penetrated 
more deeply into the way in which characters are formed and in 
which heredity transmits them from one generation to another. 
It is no wonder that Mr. Bateson and his followers speak in 
terms of animated expectation : 
“The breeder may proceed to build up synthetically, 
character by character, the plant or animal which he requires.” 
(Punnett, Mendelism, p. 58.) 
“ Mendel’s clue has shown the way into a realm of nature 
which for surprising novelty and adventure is hardly to be 
excelled. It is no hyperbolical figure that I use when I speak 
of Mendelian discovery leading us into a new world, the 
very existence of which was unsuspected before.” (Bateson, 
Inaugural Lecture, p. 4.) 
So far, then, from biology we have laid before us an increased 
range of influence for heredity. The human interest lies in the 
