His bad habits, of which he is often not aware, have brought weakness and disease upon him.
These conditions prevent him from doing his best mentally and physically.
Of course, most people are well enough to attend to their work, but nearly all are suffering from some ill, mental or physical, acute or chronic.
The average individual is of less value to himself, to his family and to society than he could be.
It is natural to be healthy, but we have wandered so far astray that disease is the rule and good health the exception.
