Physical health conditions directly influence mental and moral capacities, and narcotics or stimulants degrade intellectual tone.

Original passage

It must be kept before the people that the right balance of the mental and moral powers depends in a great degree on the right condition of the physical system. All narcotics and unnatural stimulants that enfeeble and degrade the physical nature tend to lower the tone of the intellect and morals. Intemperance lies at the foundation of the moral depravity of the world. By the indulgence of perverted appetite, man loses his power to resist temptation.