174 A Defence of Mendel's 



waltzing character in mice being also a recessive), and that 

 the "wild grey" form is one of the commonest heterozygotes 

 -there appearing, like the yellow cotyledon-colour of peas, 

 in either of two capacities, i.e. as a pure form, or as the 

 heterozygote form of one or more combinations*. 



Professor Weldon refers to both Crampe and von 

 Guaita, whose results show an essential harmony in the 

 fact that both found albino an obvious recessive, pure 

 almost without exception, while the coloured forms show 

 various phenomena of dominance. Both found hetero- 

 zygous colour-types. He then searches for something that 

 looks like a contradiction. Of this there is no lack in the 

 works of Johann von Fischer (11) an authority of a very 

 different character whom he quotes in the following 

 few words : 



" In both rats and mice von Fischer says that piebald rats 

 crossed with albino varieties of their species, give piebald young 

 if the father only is piebald, white young if the mother only is 

 piebald." 



But this is doing small justice to the completeness of 

 Johann von Fischer's statement, which is indeed a pro- 

 position of much more amazing import. 



That investigator in fact began by a study of the cross 

 between the albino Ferret and the Polecat, as a means of 

 testing whether they were two species or merely varieties. 

 The cross, he found, was in colour and form a blend of the 

 parental types. Therefore, he declares, the Ferret and the 



* The various " contradictions " which Professor Weldon suggests 

 exist between Crampe, von Guaita and Colladon can almost certainly 

 be explained by this circumstance. For Professor Weldon " wild- 

 coloured" mice, however produced, are "wild-coloured" mice and 

 no more (see Introduction). 



