D. Heron 
363 
reported from Bexley have been rejected as the relatives in the other London 
County Asylums could not be traced, for no instance has been included unless full 
particulars could be obtained." 
It is thus clear that not all the cases could be traced and that there was 
special difficulty in tracing the older cases. What is the effect of a selection 
of this kind ? A study of the following hypothetical cases may serve to throw 
some light on this point. 
TABLE IL 
Anticipation or Antedating in Insanity. Hypothetical Examples to 
show ike Effect of Dr Mott's Selection of Gases. 
First Example 
Second Example 
Mother: Born 
Married ... 
Became Insane and admitted to Asylum 
Age at First Attack 
Died 
Son : Born 
Became Insane 
Admitted to Asylum 
Age at First Attack 
1873 
1893 
1913 
40 
1914 
1833 
1853 
1873 
40 
1874 
1894 
1894* 
1914 
0 
1854 
1914 
1914 
60 
The mothers in those two examples have exactly parallel careers. In each 
case the mother became insane at the age of 40 and only lived one year in the 
asylum. In the first case the son was a congenital idiot but was only admitted to 
an asylum at the age of 20. The age of onset in this case is taken at 0 years and 
the case shows marked "anticipation." In the second case the mother also became 
insane at the age of 40, the son not till the age of 60, 40 years after his mother's 
death. The second example thus tells against the Law of Anticipation. Are 
these two cases equally likely to appear in Dr Mott's data ? 
In the first case mother and son are in the asylum at the same time and were 
admitted within a year of each other. It is very improbable that the relationship 
would escape notice and such a case is almost certain to be recorded. In the 
second case, however, the son is not admitted to an asylum till 40 years after his 
mother's death. Even if the family remained in the same area for 40 years after 
the mother's death, it would obviously be very difficult to connect the histories of 
mother and son. This case, which tells against the Law of Anticipation, is 
almost certain to escape notice. A spurious anticipation or antedating is thus 
inevitable owing to the method of collecting the data. 
It has also been pointed out that Dr Mott has made no allowance for those 
who are mentally normal at the time the record is made but may subsequently 
* Congenital Idiot. 
