i8yg.] 
or the Natural Duration of Life. 
745 
dismiss from our minds the arguments put forward by Dr. 
Beard in support of his theory ; but as there is no likelihood 
of such a state of perfection being reached, at all events in 
the present generation, it will be well to consider the condi- 
tions which favour the brain-worker, with the view of 
extending some of them to the muscle-worker, or at any 
rate of improving his social and intellectual condition. 
The causes to which Dr. Beard attributes the greater 
longevity of the brain-working classes are — i. The inherent 
and essential healthfulness of brain-work. 2. Brain-workers 
have less worry, and more comfort and happiness, than 
muscle-workers. 3. Brain-workers live under better sani- 
tary conditions than muscle-workers. 4. The nervous 
temperament, which usually predominates in brain-workers, 
is antagonistic to fatal, acute, inflammatory disease, and 
favourable to long life. 5. Brain-workers can adapt their 
labour to their moods, and hours and period of greatest 
capacity for labour, better than muscle-workers. 
The study of vital statistics led Dr. Beard, moreover, to 
the conclusion that, other conditions being the same, the 
greater and richer the brain the greater the longevity ; and 
he shows that the greatest men of the world have lived 
longer, on the average, than men of ordinary ability in the 
different occupations by fourteen years ; six years longer 
than physicians and lawyers ; nineteen or twenty years 
longer than mechanics and day labourers ; from two to three 
years longer than farmers ; and a fraction of a year longer 
than clergymen, who are the longest-lived class in our 
modern society. The causes of this exceptional longevity 
are — 1. Great men usually come from healthy, long-lived 
ancestors. 2. A good constitution usually accompanies a 
good brain. 3. Great men who are permanently successful 
have correspondingly greater will than common men, and 
force of will is a potent element in determining longevity. 
4. Great men work more easily than ordinary men. 
