74 ILLINOIS ACADEMY OF SCIENCE 
than twenty-five per cent of which is avoidable. This great 
economic waste should cause capital, labor, and the community 
to realize that of all the instruments used in the production of 
wealth and happiness, none is so delicate, so sensitive, or so 
indispensable as the human machine. The capitalist will find 
it excellent economy to carefully supervise its operation, to 
prevent it from being injured by dust or corroded by chemicals. 
It will be an invaluable advantage to the employee to learn its 
use so as to protect it from destruction by ignorance and care- 
lessness. The nation must preserve it, or forever give up the 
dream of commercial supremacy. 
Diabetes, cirrhosis of the liver, cancer, vascular degeneration 
organic heart and Bright’s disease are becoming more frequent 
before sixty. Many individuals are dying prematurely when 
as a result of training and experience, they should be of the 
greatest value. Thirty-six per cent of the deaths between forty 
and fifty and fifty-nine per cent between fifty and sixty are due 
to so-called degenerative diseases. 
The expectation of life has increased for all persons up to 
a point between thirty-five and forty. For all ages above 
forty, there is a constantly increasing diminution of the dur- 
ation of life, varying from six months at forty, to three years 
and three months at eighty-five. Tissue heredity may be a 
factor in the reduction of expectancy after forty. Its import- 
ance, however, must be small as compared to the influence of 
environment, the intemperance of food and alcohol, the harmful 
effect of occupation and the latent injuries of infectious dis- 
ease. 
The lack of personal hygiene, irregular employment, im- 
providence, bad housing, and low physical stamina cause a 
high mortality of the mentally defectlve. Over one million of 
our population is made up of the unfit, delinquent, insane, 
and criminal. We have 187,000 inmates in our hospitals for 
the insane; 480,000 prisoners; and, approximately 500,000 
feeble-minded. These are the drift-wood of industry; the 
retarders of classmate and teacher; the procreators of the un- 
fit; and, under our present social system, the most common 
cause for the travesty of justice. Syphilis, alcohol and hered- 
ity are potent factors in the production of mental deficiency, a 
condition, therefore, largely preventable. 
