VARIATION AND HEREDITY US 



ness because it is correlated wit r fa another 

 vfl.rfc.tinn of greater momentum or vital value. 

 Another result of modern studies on varia- 

 tion requires to be stated very cautiously. 

 Evidence is accumulating to show that 

 ojffa.m'( st.niff.nrp. may .paqa with seeming 

 abruptness from one position of equilibrium 

 tojannlher. Changes of considerable amount 

 sometimes occur at a single leap. These 

 bfygque changes are called "discontinuous 

 variations/' or sometimes "sports." and n in 

 certain cases.. " mutations . ' ' There is nothing 

 new in the suggestion that, evolution, may 

 sometimes have been by leaps and ...bqi;nds- 

 for this was a favourite idea of Cuvier's 

 evolutionist contemporary and antagonist, 

 Etienne Geoff roy Saint-Hilaire; and it was 

 also a pet heresy of Huxley's. Tfr^re is 

 ll r>1 '' 7 ^ r>y hat 



ous variations do Qcur, for they correspond 



' 



What is new is that we are beginning to 



fl.PP.1 1 TY11 1 1 a.t.P fn.P-t.g JTl rpp'nrrl trfc tlypir ^rP- 



Sir Francis Galton compared organic 

 structure to a polygonal model, so shaped as 

 to stand on any one of its sides. "The model 

 and the organic structure have the cardinal 

 fact in common, that if either is disturbed 



