378 Recent Studies of the Inlierltanee Factor In Insanitjj 
TABLE IX. 
Sliniuing Anticipation in Age at Death. C. FatJiers and First-horn 
Children who died in. their FatJiers' Lifetime. 
(Reigning Houses of Europe : 18th Century.) 
First-born Children 
Age at Death 
Fathers 
dying in th«ir 
Fatliers' lifetime 
0— 9 
89 
10—19 
11 
.20—29 
16 
30—89 
6 
10 
kO—lt9 
20 
5 
50—59 
32 
2 
60—69 
33 
711 — 79 
oz 
SO— 89 
10 
Totals 
133 
133 
Percentage dying under 20 
0 
75-2 
Average Ago at Death ... 
62 
10 
Anticipation 
52 
It is now possible to illustrate the effect of the principal fallacies which vitiate 
Dr Mott's conclusions. In the first place he has dealt with families which are 
largely incomplete and has collected his material in such a way that cases in 
which the insanity of parent aud child is contemporaneous are the most likely to 
be recorded ; in the second place he has directly compared parent and child with- 
out allowing for the fact that practically no parent can become insane before 20, 
while there is no limitation of this kind among the offspring of these insane 
parents. 
In Table IX and Fig. 13 we see the effect of dealing with incomplete families 
in which the children died in their fathers' lifetime. There we get an anticipa- 
tion of 52 years. If we get rid of the first and second fallacies involving a 
selection of cases by dealing with every family, as shown in Table VII and Fig. 7, 
the anticipation falls to 26 years. If we get rid of the third .source of fallacy 
also, by comparing the fathers with the first sons who have childi'en, as in Table VII 
and Fig. 8, then the anticipation falls to less than a year. The Law of Antici- 
pation or Antedating has thus in Dr Mott's case no foundation, in fact it is a 
spurious result of the mode of collecting and interpreting data. 
Now Dr Mott has not only asserted that this " Law " applies to insanity but 
has also drawn the conclusion that the offspring of insane parents if still normal 
