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 heterozygous 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 proposition 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 Polecat are two distinct species, because, “as everybody ought to know,” “_The result of a cross between albino and normal [of one species] is always a constant one, namely an offspring like the father at least in colour_[135],” [135] “Das Resultat einer Kreuzung zwischen Albino- und Normal-form ist stets, also, constant, ein dem Vater mindestens in der Färbung gleiches Junge.” This law is predicated for the case in which both parents belong to the same species. whereas in _crosses_ (between species) this is _not_ the case. And again, after reciting that the Ferret-Polecat crosses gave intermediates, he states: “But all this is _not_ the case in crosses between albinos and normal animals within the species, in which always and without any exception the young resemble the father in colour[136].” [136] “Dieses Alles ist aber _nie_ der Fall bei Kreuzungen unter Leucismen und normalen Thieren innerhalb der Species, bei denen _stets und ohne jede Ausnahme die Jungen in Färbung dem Vater gleichen_.” These are admirable illustrations of what is meant by a “_universal_” proposition. But von Fischer doesn’t stop here. He proceeds to give a collection of evidence in proof of this truth which he says “ought to be known to everyone.” He has observed the fact in regard to albino mole, albino shrew (_Sorex araneus_), melanic squirrel (_Sciurus vulgaris_), albino ground-squirrel (_Hypudaeus terrestris_), albino hamster, albino rats, albino mice, piebald (grey-and-white or black-and-white) mice and rats, partially albino sparrow, and we are even presented with two cases in Man. No single exception was known to von Fischer[137].