366 STUDIES, SCIENTIFIC AND SOCIAL chap. 



main materials on which natural selection works. But 

 this is altogether erroneous. No doubt they would reject 

 nine-tenths of Mr. Bateson's cases as being simply mon- 

 strosities, which neither have nor could ever have had any 

 part in the production of new species ; but they always 

 recognise that genera, and even species are sometimes 

 characterised by a difference in the number or arrange- 

 ment of serial parts — as of vertebrae, ribs, teeth, or mark- 

 ings, and that variations of this kind do sometimes, 

 though in comparatively few cases, form the raw material 

 on which natural selection works. As development seems 

 almost always to have proceeded by reduction from large 

 and indefinite numbers of serial parts to the minimum 

 number compatible with the maximum of utility, any in- 

 crease in number occurring now, may be, as is usually 

 considered, a form of reversion, though Mr. Bateson denies 

 that there is any such thing in nature. This diminution 

 in number may have occurred either by a gradual diminu- 

 tion in size and ultimate disappearance, as when limbs of 

 the higher animals have been lost, in whales, the apteryx, 

 snakes, &c. ; or it may sometimes have been abrupt, which 

 means that the rudiment of the part ceased to develop at 

 an early embryonic stage. Either mode is quite in har- 

 mony with the views of Darwinians, and not very much 

 seems to be gained by terming the former "continuous" 

 and the latter " discontinuous," especially when this last 

 term is held to include almost every kind of monstrosity. 



Organic Stability as a Factor in Evolution. 



We have now to consider an equally important, though, 

 as I think, an equally unsubstantial novelty — the view 

 that there are " definite positions of organic stability," 

 which alone are sufficient to mould races " without any 

 help whatever" from natural selection. This view ap- 

 pears to have originated with Mr. Francis Galton, and 

 was first stated in his work on "Natural Inheritance," 

 and again in his Royal Society paper on " Thumb and 

 Finger Marks." The same view is adopted by Mr. 

 Bateson ; and in an article on " Discontinuity in Evolu- 



