(一) 化学物质的致癌作用的发现,追溯起来,可以说是始于1775年有关扫烟囱工人阴囊皮肤癌的描述以及一系列英国外科学家的有关报告。在研究肿瘤的病因中,Schmahl指出,人体肿瘤(carcinoma)发生的因素可以概括为三方面,即反映个体状态的素因(disposition)、年龄(age)和对环境中致癌因素的暴露(exposition): (A) The discovery of the carcinogenic effects of chemical substances can be traced back to the description of the scalp skin cancer of the chimney sweepers from 1775 and a series of reports by British expatriates. In studying the causes of cancer, Schmahl pointed out that the occurrence of human carcinomas can be summarized in three aspects: the disposition, the age, and the exposition of the oncogenic factors that reflect the state of the individual: