540 
ing and killing those best fitted to be parents of vigorous offspring. 
It is a fact that the Athenian population was permanently reduced by 
this epidemic, and perhaps malaria, which appears to have become 
endemic in Attica soon after 430, found a people already weakened 
and less able to resist its ravages. 
NOTE 
I he influence of diseases on historical development will obviously 
be mainly through their effects in weakening individual nervous 
systems, and, as a result of this, individual character. Now it seems 
\\ell established that all infectious fevers play an important part in 
the etiology of the psychoses and neuroses. Typhoid especially is 
incontestably a cause of psychasthenia, and often profoundly alters 
the whole nervous system. So also influenza. The number of 
se\ ere infectious maladies prevalent throughout Roman history is 
well known. After the great outbreak of pestilence in the time of 
Marcus Aurelius, it kept reappearing from time to time for a century 
or more. 
Another point deserving consideration is this :—Is it true that the 
neurasthenic person is relatively immune to other and more imme- 
lately dangeious diseases? Dr. Beard, whose studies of neuras¬ 
thenia are so well known, asserted this positively-though the 
exp a nation he gives seems slightly fanciful* Dr. V. C. Vaughan, 
examined the matter of the typhoid outbreaks in the American 
army camps at the time of the Spanish war, informed the writer that 
e ever seemed to select the soundest men. If this be so, then a 
g ontinuance of severe infectious maladies would operate not only 
, mUCh nerVOUS debllit y- but also by a kind of inverse 
Deonlp SC eCtl ° n t0 ebmina te the relatively sound elements in a 
Droblf'inc J tha \ l * 1<? biological method of approaching historical 
cease ;r r 1 r S r beCnb i egUn : We hope for real progress, and may 
tized virtue^ ^ ex ? dnatlon of historical developments on hyposta- 
step to ; nStitUti ° nS and the ^ But. as a prehminary 
clarify our kno^'^ biology to Roman history, we need to 
human character oTd ° t What WCre the changes in the average 
in time. One la P eri °d, and the order of their development 
*Sexi7TTv--- bc sco Ptical as to the extent and accuracy 
• exual Neurasthenia, by Dr~G jvTDT—^-- 
y c»r. O. M. Heard, 4th Ed., pp. 63-4, 72-3, 76-8, 116. 
