372 Recent Studies of the Inhei itwwe Factor in Inscmity 
TABLE VII. 
Showing Anticipation in Age at Death. A. Fathers and Children. 
(Reigning Houses in Europe — 18th Century.) 
Age at Death 
Father-s 
First-born 
Children 
Fathers 
Firdt Sons wlio 
had children 
0 — 9 
10-19 
20—29 
o yj — o t-f 
40—49 
50—59 
60—69 
70—79 
80—89 
90 and over 
6 
45 
70 
77 
62 
18 
95 
11 
21 
1 8 
iO 
31 
34 
37 
33 
14 
4 
Q 
O 
31 
54 
58 
46 
12 
8 
iO 
39 
39 
44 
54 
13 
1 
Totals 
294 
294 
213 
213 
Percentage dying under 20 
0 
36-1 
0 
0 
Average Age at Death ... 
61 
36 
60 
59 
Anticipation 
25 
1 
third of Dr Mott's fallacies, in that no allowance has been made for the fact that 
the parental group is limited to ages over 20 while more than a third of the off- 
spring die under 20. The effect of this selection can be removed almost entirely 
by taking instead of the first-born child, the first son who married and had at least 
one child. There are in all 213 such cases and we see that there is now no 
anticipation. The difference between the average ages at death is less than a year 
and by removing the artificial selection we have got lid of all anticipation or 
antedating. 
These facts are also shown graphically in Figs. 7 and 8. The horizontal scale 
gives the age at death in 10-year groups while the vertical scale gives the actual 
numbers of parents and offspring dying in each age group. The diagram on the 
left shows marked anticipation, and should be compared with Dr Mott's diagram 
(Fig. 1) in which the ages at onset of insanity of father and child are compared. 
When, however, we get rid of the selection of cases by taking only sons who have 
had children, then there is no anticipation. 
If we compare the distributions of age at death in mothers and children we get 
exactly the same results. The facts are shown in Table VIII. 
We see that the first-born children died on an average 18 years before their 
mothers, but when we compare the age at death of mothers and the first son in 
