1875.] Longevity of Brain- Workers. 431 
Between 1864 and 1866, while preparing a thesis for gradu- 
ation, I obtained statistics on the general subject of the 
relation of occupation to health and longevity that convinced 
me of the error of the accepted teachings in regard to the 
effect of mental labour. These statistics, which were derived 
from the registration reports of this country and of England, 
and from a study of the lives of many prominent brain- 
workers, were incorporated in an essay on the subject that 
was delivered before an Association of Army and Navy 
Surgeons in New Orleans in 1863, and afterwards published 
in the ‘‘ Hours at Home”? Magazine. ‘The views I then ad- 
vocated, and which [enforced by statistical evidence, were :— 
Ist. That the brain-working classes—clergymen, lawyers, 
physicians, merchants, scientists, and men of letters,—lived 
very much longer than the muscle-working classes. 
and. That those who followed occupations that called both 
muscle and brain into exercise, were longer lived than those 
who lived in occupations that were purely manual. 
3rd. That the greatest and hardest brain-workers of history 
have lived longer on the average than brain-workers of 
ordinary ability and industry. 
4th. That clergymen were longer lived than any other 
great class of brain-workers. 
5th. That longevity increased very greatly with the ad- 
vance of civilisation ; and that this increase was too marked 
to be explained merely by improved sanitary knowledge. 
6th. That although nervous diseases increased with the 
increase of culture, and although the unequal and exces- 
Sive excitements and anxieties attendant on mental occupa- 
tions of a high civilisation were so far both prejudicial to 
health and longevity, yet these incidental evils were more 
than counterbalanced by the fact that fatal inflammatory 
diseases have diminished in frequency and violence in pro- 
portion as nervous diseases have increased; and also that 
brain-work is, per se, healthful and conducive to longevity. 
Many of these views have since received various and 
powerful confirmation, and by a number of independent 
observers.* The statistics on this subject I have endeavoured 
* Those who desire to obtain the detailed fa&s on this subje@ are referred to 
my Essay 1n “‘ Hours at Home” (OG., 1867); to my series of paperson ** Hygiene 
for Students,” in the ‘‘ College Courant” (1869); to my “ Home Physician,” p. 
380; to Dr. Derby’s ‘ Registration Reports of Massachusetts”? and Farr’s 
‘Registration Reports of England ” (Supplement to 22nd) ; to Dr. Edward Jar- 
vis’s Papers on the ‘‘ Increase of Human Life,” in ‘* Atlantic Monthly” (O@., 
Nov., and Dec., 1869); to Dr. Elam’s ‘‘ Physician’s Problems;” Hon. B. G. 
Northrup’s ‘‘ Report of the Connecticut Board of Education” (1869, pp. 61-74) ; 
and to the “ Reports of the Life Insurance Company for Clergymen’”’ (Bible. 
House, N. Y.). 
VOL. VI. (N.S.) ag 
