南开大学元素有机化学研究所的一间宽敞明亮的大教室里,整整齐齐地坐满了人,他们中间有科研人员、工农兵学员和技工班的青年工人,都在全神贯注地听课。主讲人是一位白发苍苍的老教师。他神态轩昂,手持教鞭,指着挂在黑板上的图表,讲授世界各国农药发展状况。这就是已经八十二岁高龄的有机化学家杨石先教授。打倒“四人帮”,知识分子心欢畅。杨石先看到在 Nankai University Institute of Elemental Organic Chemistry, a bright and spacious large classrooms, neatly filled with people, among them scientific research workers, workers and peasants and soldiers and mechanic class young workers, are attentively listening to lectures. The speaker is a pale old teacher. His demeanor, holding a pointer, pointing to the chart hanging on the blackboard, teach the world’s pesticide development. This is Professor Yang Shixian, an organic chemist who is already 82 years old. Down with the “gang of four,” intellectuals happy heart. Yang Shi first saw in