Why does God allow sickness?

Criminals are here classed, according to deeds—all are placed in rank, and the disease removed by education, for sin is a disease of the mind either organic—or brought out by surrounding conditions. Some are made to heal the others—to restore what the other lacks—thus equalise each other. 

You would be astonished to see sin-sick lives, waiting the physician's change. 

They are not cooped up in cells and chained, but are placed in the glorious scenery of free air, lovely woods and fields to infill them with a sense of their within loneliness and lack of worth.