D. Heron 
365 
Dr Mott has arisen. Unfortunately this is the only pedigree for which sufficient 
details have been given to enable its completeness to be tested. The pedigree 
and Dr Mott's description of it are as follows : 
"A.B., an alien Jew, aged 54, was admitted to an asylum for the first time sufiering from 
involutional melancholia ; he has a sister who has not been in an asylum, but, as events turned 
out, bore the latent seeds of insanity. The man is married to a healthy woman who bore him a 
large family ; the first five are quite healthy, then comes a congenital imbecile epileptic (cong.)*, 
then two healthy children followed by a daughter who becomes insane at 23, then a son insane 
at 22, and lastly two children who are up to the present free from any taint. The sister of A.B. 
is married and has a family of ten, seven girls and three boys ; one of the females was admitted 
to the asylum at the age of 19, and since this pedigree was constructed a brother of hers has 
been admitted aged 24. Half-black + circles are insane. The pedigree is instructive ; it shows 
direct and collateral heredity ; it also shows remarkably well the signal tendency to the 
occurrence of insanity at an early age in the children of an insane and potentially insane 
parent." 
• = Insane. 
13 children : 9 Alive, 4 Sons, 5 Daughters. 4 Dead. 3 Insane. 
Fig. 3. Pedigree to illustrate the effect of Dr Mott's selection of cases. 
F. W. Mott: "Heredity and Eugenics in relation to Insanity." Problems in Eugenics, p. 413. 
This pedigree was given as above in July 1912, and in an address previously 
delivered before the Manchester Medical Society on Oct. 4, 1911, Dr Mott gave 
the same pedigree, but without any reference to the nephew of A.B. (brother of 
the girl who became insane at 19) who became insane "since the pedigree was 
constructed," so that this man became insane between 1911 and 1912 and this 
serves to " date " the pedigree. 
Now it should be noted that at least five of the children of A.B. are over 23 years 
of age and up to the present time healthy. But all these children are alive and if 
any one of them afterwards becomes insane, the average age of onset of insanity in 
the children will be raised — and it is clear that the more incomplete the pedigree 
the greater the amount of spurious anticipation. Again Dr Mott states that in 
* This does not agree with Dr Mott's pedigree which gives the congenital case as the seventh 
instead of the sixth child. 
t According to our usual custom, they are represented by full black circles in Fig. 3. 
Biometrika x 47 
