Description: Segment 1 Loveless describes Ernest Kennaway's research into carcinogenesis. He shows a chemical diagram for nitrogen mustard which is a known chemical carcinogen. Time start: 00:00:00:00 Time end: 00:06:19:00 Length: 00:06:19:00 Segment 2 Loveless shows the chemical diagram of dibenzanthracene and describes its properties. Time start: 00:06:19:00 Time end: 00:10:27:00 Length: 00:04:08:00 Segment 3 Brookes takes over from Loveless. He shows the chemical diagram for acetylamino fluorine and describes its properties. Time start: 00:10:27:00 Time end: 00:17:00:00 Length: 00:06:33:00 Segment 4 Brookes shows the chemical formula of dimethyl nitrosamine and dimethyl sulphate and describes their properties. He then shows the chemical formula for guanine, one of the four constituent bases of DNA. Time start: 00:17:00:00 Time end: 00:23:19:00 Length: 00:06:19:00 Segment 6 Mcpherson shows diagrams of the mechanism for cell change by SV40 and Rous sarcoma viruses. Further diagrams are used to ilustrate techniques for finding virus-specific nucleic acid. Time start: 00:30:32:00 Time end: 00:35:41:00 Length: 00:05:09:00. Segment 7 Mcpherson summarises the lecture. Time start: 00:35:41:00 Time end: 00:39:27:01 Length: 00:03:46:00