Variation and Heredity 273 



specimens. But it does not at all follow because these inter- 

 mediate forms have been found to exist, that they were the 

 very stages that were passed through in the course of evolu- 

 tion. Counter evidence exists in abundance, not only of the 

 appearance of considerable sports, but of their remarkable 

 stability in hereditary transmission." Comparing such an 

 apparently continuous series with machines, Galton con- 

 cludes, " If, however, all the variations of any machine that 

 had ever been invented were selected and arranged in a 

 museum, each would differ so little from its neighbors as to 

 suggest the fallacious inference that the successive inven- 

 tions of that machine had progressed by means of a very 

 large number of hardly discernible steps." 



Bateson, also, in his " Materials for the Study of Variation," 

 speaks of the two possible ways in which variations may arise. 

 He points out that it has been tacitly assumed that the tran- 

 sitions have been continuous, and that this assumption has 

 introduced many gratuitous difficulties. Chief of these is 

 the difficulty that in their initial and imperfect stages many 

 variations would be useless. " Of the objections that have 

 been brought against the Theory of Natural Selection, this 

 is by far the most serious." He continues : " The same 

 objection may be expressed in a form which is more correct 

 and comprehensive. We have seen that the differences be- 

 tween species on the whole are Specific, and are differences 

 of kind forming a discontinuous Series, while the diversities 

 of environment to which they are subject are, on the whole, 

 differences of degree, and form a continuous Series; it is, 

 therefore, hard to see how the environmental differences can 

 thus be made in any sense the directing cause of Specific 

 differences, which by the Theory of Natural Selection they 

 should be. This objection of course includes that of the 

 utility of minimal Variations." 



" Now the strength of this objection lies wholly in the sup- 

 posed continuity of the process of Variation. We see all 



