Work of Bateson and De Vries 
delusion that mutations or “sports” are rare in 
nature, and that when these do happen to occur 
they must of necessity be swamped by inter- 
crossing. 
However, the discovery of the Abbé Mendel’s 
account of his experiments on breeding mongrel 
sweet peas has opened the eyes of many 
zoologists, so that they have at last learned 
what practical breeders have known for untold 
years—namely, that sports have a way of per- 
petuating themselves. Moreover, Mendel was 
able to give a theoretical explanation of his 
discoveries, with the result that the believers 
in discontinuous variation have largely increased 
in number of late. 
While we are unable to see eye to eye with 
Professor Bateson in all things, we gladly recog- 
nise the immense value of his work. Had his 
statements in 1894 received the attention they 
merited, zoological theory would to-day be con- 
siderably more advanced than it actually is. 
Professor De Vries has gone farther than 
Bateson, having engrafted upon the Darwinian 
hypothesis the theory of mutations. He has 
done no small amount of experimental work, and 
has undoubtedly thrown much new light on the 
ways in which species arise. He is purely a 
botanist, so that he argues only from plants. 
Nevertheless, we believe that some of his con- 
clusions are applicable to animals. We are far 
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