Tumors in Drosophila are in many ways similar to atypical growths in mammals, although they are dissimilar in others (6). A frequent question concerning these tumors is whether carcinogens alter their incidence. This has been tested by treat ing a tumor stock of Drosophila with 20-methylcholanthrene and is reported at this time. In a previous study (4) it was shown that the lethal mutation rate...

This paper introduces and outlines a methodology that may be unfamiliar to some qualitative researchers: Membership Categorisation Analysis (MCA). The first section of the paper explains the basic principles of MCA and why it is a valid method for exploring the power of categorisations in texts and talk. Additionally, it explains why MCA differs from other forms of qualitative data analysis. Th...