222 Transactions. 



The answers being of so negative a character, some explanation or apology 

 would appear necessary to justify the existence of this paper. This is sup- 

 plied by the report on the mental hospitals of the colony for 1906, issued 

 by Dr. F. Hay, Inspector-General of Mental Hospitals. In that report are 

 given some remarkable deductions from the statistics of insanity in New 

 Zealand, and the questions above are not merely raised and answered in the 

 affirmative, but in each case the differences rej^resented as existing are of a 

 character that may fairly be described as sensational. Dr. Hay further 

 theorizes on the influences that have brought these differences into being, and 

 goes so far as to consider the advisability of Governmental action with a 

 view to giving these influences less free scope in the future. If, then. Dr. 

 Hay's deductions are more or less unfounded, it is highly important that the 

 fact should be clearly demonstrated, both in the interests of statistical and 

 sociological science and of public policy. It is the more necessary as Dr. 

 Hay's conclusions on two of the questions here raised are again brought 

 forward in the report for 1907. 



The New-Zealand-born and the Immigrant. 



The report represents the native-born in New Zealand as far less liable 

 to insanity than the immigrant. " The outstanding feature disclosed by 

 these calculations," it says, " is the remarkably low incidence of insanity 

 among New-Zealand-born." The figures finally given as representing the 

 situation are : — 



Not New-Zealand-born . . . . 1 insane in 118-9 



New-Zealand-born . . . . 1 insane in 246-9 



indicating, apparently, a tendency to insanity in the immigrant more than 

 double that in the native-born. 



Now, in spite of these figures, I may say at once that this or any similar 

 deduction will be shown to be absolutely unfounded in fact. But I shall 

 first endeavour to make clear the nature of the mistake made in the report. 

 Dr. Hay himself modified his figures and moderated his conclusions in com- 

 paring the immigrant with the native-born by allowing for the facts that 

 (1) there is comparative immunity from insanity below the age of twenty, 

 and that (2) the age of the large majority of immigrants is from twenty 

 upwards, nearly the whole of our population under twenty being native-born. 

 He did this by eliminating those under twenty and comparing only the 

 populations of the two classes over twenty years of age. This altered his 

 first figures considerably. The original figures were — 



New-Zealand-born . . . . 1 insane in 613-6 



Not New-Zealand-born . . . . 1 insane in 129-2 



The modified figures are, as before stated, — 



New-Zealand-born . . . . 1 insane in 2-46-9 



Not New-Zealand-born . . . . 1 insane in 118-9 



This amendment was in the right direction. It removed the influence 

 of that portion of the New-Zealand-born population under twenty, amount- 

 ing to considerably more than one-half of the total, to which corresponded 

 only a very small fraction of the immigrant population, and which was under 

 the age of substantial liability to insanity. But this manner of correction 

 was not carried nearly far enough. The report deals with the question as if 



