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ANNOUNCEMENTS 
daughters. In general our Histories show that nomadic fathers may 
have no nomadic sons, but there is no case of a nomadic mother of more 
than two children none of whom is nomadic. Thus our data support 
the hypothesis that the paralysis of the control of the momadic impulse 
is a sex-linked trait. 
Other hypotheses, such as (1) that nomadism is, like the beard in man, 
essentially a male characteristic, and (2) that nomadism is less common 
among women than among men solely because it is less feasible for women 
to live a nomadic Hfe, are not at all supported by a full consideration 
of the facts. 
Finally, the frequent association of nomadic impulses with psychoses 
both periodic (depressions, migraine, hysteria, sprees) and constitutional 
(feeblemindedness and dementia-precox) is explained as follows. The 
wandering instinct is, in man, fundamental, basic. In the more intel- 
lectual part of the population, under the influence of the mores, this im- 
pulse is more or less satisfactorily repressed where there is good reason 
why it should be, except in families of periodics where the inhibitions 
are temporarily paralyzed and the person 'breaks out.' Among consti- 
tutional mental inferiors on the other hand, the inhibitions may be 
slightly developed and such persons show a constant roving tendency — 
as ne'er-do-wells, some tramps, the gypsies and other nomadic tribes. 
All classes of nomadism can thus be ascribed to one fundamental cause, 
the nomadic instinct. In addition, since the more intelligent represen- 
tatives of the nomadic race are able, in a measure, under ordinary cir- 
cumstances, where it appears desirable, to inhibit their impulses, we 
find that, with such people, the unstable, wandering impulse is apt to 
be associated with a periodic disturbance that renders inoperative the 
inhibitory machinery; these disturbances are not the fundamental cause 
of the nomadic impulse but merely permit it to show itself. The capac- 
ity for such periodic disturbance is sex-linked. 
The complete paper will probably appear in the Journal of Nervous 
and Mental Disease and in the Bulletin of the Eugenics Record Office. 
ANNOUNCEMENTS 
WILLIAM ELLERY HALE LECTURES 
The third course of lectures on the William Ellery Hale Foundation will 
be given by Professor Thomas Chrowder Chamberlin, of the University of 
Chicago, at the next annual meeting of the Academy, on "The Evolution of 
the Earth." 
