54 THE TREND OF THE RACE 
the parents was not excluded in the statistics and the “sane” 
offspring may have been neuropathic in other ways. 
Heron’s data on this point are meagre and do not furnish 
information as to the age of the sane offspring, so it is not certain 
that they reached the period at which insanity would be devel- 
oped. Goring gives three matings between insane parents, with 
19 offspring, all sane, but we know little of their age beyond the 
fact that they were convicts. 
Several writers have brought forward evidence that particular 
types of insanity tend to run in families. Berze reports a case 
of dementia precox in a father and three sons; a case of a man, 
his daughter and her two children and several other instances with 
two or more in each family. Dr. Schuster from a statistical 
investigation of cases in the London County Asylums concludes 
that ‘‘a periodically insane son or daughter is more likely to be 
associated with a periodically insane mother or father than with 
one differently affected,” and a similar association occurs between 
insane brothers and sisters. In delusional insanity ‘‘The tend- 
ency for the affliction to run in families is very marked” and “in 
the incidence of the primary dementia of adolescence there is a 
strong correlation between members of the same co-fraternity.” 
Strohmayer finds that manic-depressive insanity frequently 
reappears in much the same form. “Es gibt kaum ein Krank- 
heitsbild, wo so einmutig die Macht des Erbfaktors anerkannt 
wird, wie beim manisch-depressiven Irresein. Alle Autoren heben 
den auffallend grossen Prozentsatz des durch Geisteskrankheit 
direkt oder indirekt belasteten Kranken dieses Schlages hervor. 
Die Angaben schwanken zwischen 75 und 85%. Ebenso stim- 
men alle Beobachter darin iiberein, das innerhalb des manisch- 
depressiven Gebeites die gleichartige verbliiffend tiberweigt.” 
Many alienists from Morel to the present time have empha- 
sized the extreme variability of the manifestations of mental 
defect and disease, and have found little tendency for the same 
type of insanity to repeat itself in successive generations. That 
particular forms of insanity are rarely transmitted as such is a 
doctrine which has been rather more frequently espoused in 
