88 THE CASE AGAINST EVOLUTION 



scent of fossil forms are irremediably speculative and conjec- 

 tural. When we are dealing with living forms, we can always 

 check up the inferences based on somatic characteristics by 

 means of genetical experiments, and in so doing we have found 

 that it is as unsafe to judge of an organism from the exclusive 

 standpoint of its external characters as it is to judge of a book 

 by the cover; for, apart from the check of breeding tests, it 

 is impossible to say just which somatic characters are geneti- 

 cally significant, and which are not. Forms externally alike 

 may be so unlike in germinal constitution as to be sexually 

 incompatible; forms externally unlike may be readily crossed 

 without any discernible diminution of fertility. ''Who could 

 have foreseen," exclaims Bateson, ''that the apple and the pear 

 — so like each other that their botanical differences are eva- 

 sive — could not be crossed together, though species of Antir- 

 rhinum (Snapdragon) so totally unlike each other as ma jus 

 and moUe can be hybridized, as Baur has shown, without a 

 sign of impaired fertility?" {Heredity, Smithson. Inst. Rpt. 

 for 1915, p. 370.) We cannot distinguish between alleged spe- 

 cific, and merely mutational (varietal), change, nor between 

 hybridizations and factorial, chromosomal, or pseudo-, muta- 

 tions, solely on the basis of such external characters as are 

 preserved for us in fossils. It is impossible, therefore, to 

 demonstrate trans-specific variation by any evidence that 

 Palaeontology can supply. The palaeontologist {pace Os- 

 born) is utterly incompetent to pass judgment on the problem 

 of interspecific relationship. As Bateson remarks: "In dis- 

 cussing the physiological problem of interspecific relationship 

 evidence of a more stringent character is now required; and 

 a naturalist acquainted with genetical discoveries would be as 

 reluctant to draw conclusions as to the specific relationship of 

 a series of fossils as a chemist would be to pronounce on the 

 nature of a series of unknown compounds from an inspection 

 of them in a row of bottles." {Science, April 17, 1922, p. 373.) 

 "When t"he modern student of variation and heredity," says 

 T. H. Morgan, "looks over the different 'continuous' 



