No. 528] SKIN PIGMENTATION IN MAN 



72^ 



two or three children albinism will not appear. Even in 

 families of four or more the possible case of albinism 

 may fail to occur. All such cases of an actual low ratio 

 of albinism are omitted from any calculation of propor- 

 tions; chiefly the accidentally high ratios are brought 

 under consideration. The actual proportions of albinos 

 to all offspring of two pigmented parents are given for 

 each family in Table XII. 



These 33 families together with two not plotted in the 

 diagrams are summarized in Table XII. 



TABLE XIII 



Xkitiikk Parent is Albinic 



] ■■:-.. !!••'.. H if. 



Taking Table XIII in its entirety there is an average 

 of 44 per cent, albinos to a family where expectation is 

 25. If we consider only the families with four or more 

 children we find the average proportion of albinos to be 

 34 per cent. If we take families with six or more chil- 

 dren the average proportion of albinos falls to 32 per 



