Chronic and toxic: General symptom is lighter, course of diseases is slow, have the head blunt the neurasthenia shape such as painful, giddy, dazed, lack of power, insomnia.

• 慢性中毒：一般症状较轻，病程缓慢，有头部钝痛、头晕、头昏、乏力、失眠等神经衰弱症状。