• Central and peripheral nervous system – Progressive sensory and motor paralysis; incoordination [Hering, Allen].
• Special senses – Degenerative changes of optic and auditory nerves.
• Spinal cord – Sclerosis-like symptoms, especially posterior columns.
• Blood vessels – Toxic effects on vascular tone, producing congestion and degeneration.
• Digestive tract – Offensive breath, coated tongue, sluggish digestion.
• Skin – Pruritus, eruptions, ulcerations from impaired nutrition.
• Metabolism – Chronic poisoning states with gradual decline in vitality.

• Rest, avoidance of exertion.
• Gentle warmth in chronic states.
• Lying down during neuralgic pains.

• Physical exertion, especially walking or climbing stairs.
• Mental strain or prolonged concentration.
• Alcohol.
• Damp cold weather.
• Night and early morning.

Profound mental weakness and dulness, as if the brain were benumbed [Hering]. Difficulty fixing attention; ideas vanish mid-thought. Apathy, disinclination for mental or physical work. In toxic states, irritability alternates with depression; suspicious, restless, unable to remain long in one place. Loss of memory, especially for recent events, accompanied by a sense of confusion and unreality [Clarke].

Vertigo on rising, with staggering gait. Dull, heavy headache, often occipital or over the eyes, worse from mental effort. Feeling of fullness in the head, with heat and throbbing. In chronic poisoning, slow deterioration of mental sharpness with constant pressure-like sensations [Allen].