EVOLUTION, CYTOLOGY AND MENDEL' 8 LA^Y8. 221 



It would be impossible to have any such compound as ABCD, but 

 we should get instead one of the four character-combinations AC, 

 AD, BC, BD. The inheritance of a single character from one grand- 

 parent would certify the inheritance of all, and thus establish an alibi 

 for the other ancestor of the same side of the house. What a resource 

 for genealogists to be able to prove that a man was no relative of his 

 grandfather, or even that he had no consanguinity with his own 

 brother! Alas that Mendel and other 'experimental evolutionists' 

 have proved that inheritance is by characters and not by chromosomes, 

 if these behave as Professor Wilson indicates. Only the so-called 

 monohybrids, those differing by a single character, would tolerate such 

 an interpretation, and the fallacy of it is obvious as soon as we re- 

 member that hybrids may be assembled with reference to two, three 

 or more characters derived from different ancestors. Moreover, Pro- 

 fessor Spillman has recently drawn from his experiments with wheat 

 concrete and detailed examples of the fact that definite proportions 

 of such combinations are permanent, since two dominant characters 

 do not antagonize each other.* Unless it be in the case where the 

 varieties crossed differ in but a single character we know of a certainty 

 that the germ-cells are not of pure descent with respect to parentage.] 

 The most that can be claimed is that they are organized reciprocally 

 with reference to the divergent 'parental characters, since it seems that 

 the different features may be distributed and recombined quite with- 

 out reference to the manner in which they were grouped in the parents. 

 In his hybrid wheats Professor Spillman finds all the combinations 

 possible under the mathematical theory of chance. How this could 

 be managed by the chromosomes our cytological friends may be able 

 to conjecture, though from the outside it looks like a rather difficult 

 question. 



Hybridization is possible only between groups of common origin, 

 and the characters which show the Mendelian effect are those on which 

 the greatest divergence has taken place. That such characters may 

 be changed about or substituted, and are able to enter freely into all 

 varieties of combination, not only does not prove that the chromosomes 

 are mechanisms of heredity, but it greatly decreases the probability 

 of mechanical theories of evolution, since it shows the facility with 

 which characters may be accumulated in normal interbreeding, before 

 the Mendelian degree of divergence has been reached. 



If two plants different in other respects are found to differ also in 



* ' Mendel's Law,' Popular Science Monthly, 62 : 269. 



t The theory of Bateson that the germ-cells are pure with respect to char- 

 acters seems to have been misunderstood both by Professor Wilson and by Mr. 

 Cannon in his ' Cytological Basis for the Mendelian Laws ' (Bulletin Torrey 

 Botanical Club, 29:657, 1902). 



