382 Recent Studies of the Inheritanee Factor in Insanity 
children after their first attack of insanity and of 31 such cases examined, 73 chil- 
dren were born after the first attack of insanity in the parent." 
But have these 148 recurrent cases been followed up to the end of the repro- 
ductive period ? Not at all. No ages are given and the cases are merely those 
which were admitted to Asylums in 1911, Dr Mott's remarks being made in 
June 1912, so that no attempt has been made to follow them up. There is no 
justification for Dr Mott's advice. 
There are many other points in Dr Mott's work which deserve detailed exami- 
nation, but time will not permit more than a brief account of a few of them. 
It should be noted, for instance, that Dr Mott has used his index of relatives 
in London County Asylums as an argument in favour of the importance of the 
inheritance factor in insanity. His argument is as follows : 
"At the present time in the London County Asylums there are 725 individuals 
so closely related as parents and offspring, brothers and sisters. A priori, this, to 
my mind, is striking proof of the importance of heredity in relation to insanity, 
for we cannot suppose that 20,000 of the 4J millions of people in London brought 
together from some random cause would show such a large number closely related 
as 3'6 7o-" 
But Dr Mott has not attempted to give, and I doubt if he ever wall be able to 
give, a satisfactory estimate of the number of relatives in even a random sample 
of the population, and the population of asylums is far from being a random 
sample of the general population — there is for instance an extraordinary divergence 
in age. Yet without definite information on this point it would be impossible to 
say whether insanity is inherited or not — that is if we had to depend solely on 
Dr Mott's data. 
It should also be noted that in these cases Dr Mott has clubbed together 
every form of insanit}^, from congenital idiocy to senile dementia, except of course 
cases due to specific infections or trauma. I myself think that course is the only 
possible one. To anyone who has studied even a few pedigrees of mental defect, 
nothing is more striking than the extraordinary number of different forms of 
mental defect that may appear in the same family. 
Seven years ago, in a First Study of the Statistics of Insanity and of the 
Inheritance of the Insane Diathesis*, I was confronted with the same problem, 
and after a full consideration of all the available data and of the opinions of those 
medical men who were best qualified to express an opinion came to the conclusion 
that the only possible course was to group all forms of insanity together, with, 
of course, the exceptions I have already indicated. The whole question was dis- 
cussed very fully in my paper and it was there suggested that an even broader 
classification might be of service. This point of view met with some criticism at 
the time but nothing has occurred to alter it, and the study of the inheritance of 
* Gallon Memoirs, No. II. (Dulau and Co.) 
