Karl Pearson 
349 
1 in 5 and 3 in 9 in generations II., III. and IV. affected or 6 in 19. This is a fair 
approximation to a third, but rather a poor one to a half There is in fact a 
deviation of 3"5 with a standard deviation of \/l9 x ^ x ^ = 2'1 79, or the deviation is 
l"61 times the s. D. The odds against such a defect ai-e more than 17'5 to 1. Of 
course not impossible but improbable. 
On the other hand there is no case in which an apparent normal marrying a 
normal has transmitted the character. In the case of IV. 11, 12, 13 and 14 there 
are considerable families, exact numbers not available, but it is known that none 
are affected. Thus it would appear that transmission through the unaffected either 
does not ever, or at least commonly, occur. 
This rule holds also for Cockayne's family and for the Bianconcini. 
IV. 2 is the only one with body pigmentless patches. As III. 1 mentioned this 
fact without special enquiry, I think we must take it that her statement with regard 
to IV. 5 and IV. 10 and to herself that they and she have no pigmentless body 
patches can be accepted. She believed that II. 1 had no such patches, but did not 
know about II. 3 or I. 2. It would seem therefore that in this family at least con- 
spicuous body patches are not frequent. It should not therefore be looked u])on as 
a piebald family in the ordinary sense. It exhibits the inheritance of a " Hare." 
