108 
Miscellanea 
are alleloraorphic characters, albinism being recessive, the marriages which can give rise to albino 
children are of two kinds only, namely (1) those between albinos of any ancestry, who are by the 
hypothesis "gametically pure recessives," and (2) those in which each individual has some albino 
ancestry, and is a " heterozygous " product. Marriages of the first kind shoidd produce albinos 
only, while a quarter of the children resulting from marriages of the second kind should bo 
albino, the rest being pigmented. Neither of these expectations is justified by Arcoleo's 
record. The three albinos produced by albino parents belonged to one family, and it is 
stated that "Gli antenati furono tutti bianchissimi," implying a considerable amount of 
all)ino ancestry; yet this family contained two pigmented brothers I Again, the most probable 
number of albinos among the 133 offspring of pigmented parents, all of whom are known to be 
capable of jiroducing some albinos, is 33'25, and the Standard Deviation of this expectation 
is Vi X i X 133 = 4-94. The observed number of albinos, namely 49, shows an excess of 15'75, or 
about 3'2 times the standard deviation, over that predicted by the Mendelian hypothesis. The 
odds against any result as large or larger than that observed, if the hypothesis be true, are nearly 
2000 to 1 ; and although this degree of improbability may not be held by some to disprove the 
hypothesis, it certainly ought not to be adduced as evidence in support of it. 
The occurrence of segregation in a non-Mendelian proportion is exactly paralleled by the 
behaviour of the character "waltzing" as opposed to normal walking in mice, recorded by 
von Guaita and Darbishire. 
The one fact which is not in apparent contradiction to Mendel's hypothesis is the behaviour 
of six albinos who married pigmented persons. One marriage was sterile ; the other five pro- 
duced altogether 24 children, all 2:)igmented. 
Taking these records in conjunction with the work of Cuenot (6) and Darbishire (5) on the 
inheritance of albinism and of other characters in mice, we see that the disappearance of a 
character such as albinism in the offspring resulting from a cross between an albino and a 
pigmented individual, and the reapjjearance of albinism in a portion of the grandchildren, 
produced when the immediate offspring of the cross are mated, may be associated with very 
different conditions of the albinos. Cuenot and Darbishire have both shown that the colour of 
the young produced by a cross-bred albino mouse, paired with a coloured mouse, depends partly 
on the colours exhibited by the ancestors of the cross-bred albino, thus showing clearly that such 
an albino, although it should be a " pure recessive " in Mendel's sense, is not gametically pure. 
Among mice there is no certain record of cross-bred albinos so impure that when paired together 
they produced pigmented young ; the case of the family recorded by Arcoleo is therefore of great 
interest, as showing that in Man even this degree of " gametic impurity " may exist in albinos. 
These results show how necessary it is that the phenomena of alternative inheritance should 
be studied in the light of fuller experimental knowledge concerning the correlations between 
cross-bred individuals and their ancestors; they show the futility of attempting to express such 
phenomena in terms of formulae based on the unproved hypothesis of gametic purity. 
Finally I would urge on ' those who have opportunity the great value of a full study of 
albinism in Sicily. In the province of Palermo, from which many of Arcoleo's cases are drawn, 
the percentage of accepted soldiers of j'ure blonde type ("con capelli biondi e con occhii celesti ") 
is given by Livi (7) as 2-1 ; that of men " con capelli biondi o rossi e con occhii celesti o grigi " is 
3'8. Albinos are naturally exempt from military service, because of their abnormal eyes, and 
therefore do not appear in Livi's table. During a recent visit to Sicily, when I walked over a 
good deal of country round Palermo with an artist friend, my attention was continually called, 
not only to albinos, but to the extraordinary fairness of many blonde persons, who were still 
slightly pigmented. It would be of great interest to know whether these blondes are more often 
related to albinos than are persons of the darker, more usual typo. 
W. F. R. W. 
